Name: low pressure vapor-assisted solution process for tunable band gap pinhole-free methylammonium lead halide perovskite films
Uploaded: 2017-09-08T11:00:00.000+00:00
Duration: 8 min 12 s
Description: Watch this Scientific Journal Video about Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films at JoVE.com

通过美国能源部科学办公室的支持, 在人造光合作用联合中心进行了钙钛矿的工艺开发、薄膜合成、结构和形态表征。根据奖项编号 DE-SC0004993 的能源。C.M.S.-F。承认瑞士国家科学基金会 (P2EZP2_155586) 的财政支持。

警告: 请在使用前查阅所有相关的材料安全数据表 (MSDS)。这些合成中使用的几种化学物质具有剧毒、致癌性和生殖毒性。内爆和爆炸风险与 Schlenk 线的使用有关。请确保检查玻璃器具的完整性, 然后再执行程序。不正确使用 Schlenk 线与液氮冷阱相关联可能会导致液态氧 (淡蓝色) 的凝结, 从而形成爆炸性。在使用真空系统、Schlenk 线和低温液体之前, 请确保专家接受适当的职业培训。在执行综合时, 请使用所有适当的安全做法, 包括使用工程控制 (油烟罩) 和个人防护设备 (安全眼镜、手套、实验室大衣、全长长裤、双脚趾鞋)。以下所述的所有步骤均在空气中的油烟罩中进行, 除非有不同的说明. 
 1. Methylammonium 卤化物的制备 <ol> <li> 到250毫升圆底烧瓶装有搅拌棒, 添加乙醇 (100 毫升) 和甲胺 (190 摩尔, 16.5 毫升, 40% 重量 在 H 2 O), 并冷却烧瓶到0和 #176; C一个冰浴. </li>
	<li> 而甲胺溶液是搅拌 (约5分钟在600革命每分钟 (rpm)), 添加 HI (76 摩尔, 10 毫升, 57% 重量 在 h 2 o) 或评论 (76 摩尔, 8.6 毫升, 48% 重量 在 h 2 o) 滴, 并密封烧瓶与隔膜. </li>
	<li> 允许反应在0和 #730 时搅动2小时; C. </li>
	<li> 将反应瓶从冰浴中取出, 并在减压 (〜50乇) 上蒸发溶剂和未挥发性成分, 在60和 #730 上装有水浴的旋转蒸发器; C 为4小时或直到挥发物被去除. </li>
	<li> 要结晶所产生的固体, 请添加温热 (〜50和 #176; C) 乙醇 (100 毫升) 并溶解残余物质. </li>
	<li> 缓慢添加乙醚 (200 毫升), 以诱导白色固体结晶. </li>
	<li> 真空过滤器混合在一个粗50毫米玻璃熔块过滤器. </li>
	<li> 回收上清液并加入二乙醚 (200 毫升), 以诱导白色固体的额外结晶。真空过滤器的混合物在第二粗50毫米玻璃熔块过滤器. </li>
	<li> 将白色固体混合在粗糙的 50 mm 玻璃熔块过滤器上, 而在真空过滤时, 将产生的粉末用乙醚洗涤三次 (每次30毫升). </li>
	<li> 在真空下干燥白色固体。本程序产生 (58.9 摩尔, 9.360 克, 77%) methylammonium 碘 (ch 3 nh 3 I) 和 (55.5 摩尔, 6.229 g, 73%) 的 methylammonium 溴 (ch 3 nh 3 Br). </li>
	<li> 存储在黑暗中, 在室温下干燥, 以减少随着时间的推移分解. </li>
</ol> 2。Methylammonium 铅卤化物的制备 (CH 3 NH 3 PbI 3 x Br x ) 薄膜 6 、 20 <ol> <li> Schlenk 管的预调节 <ol> <li> 将50毫升 Schlenk 管 (直径2.5 厘米) 装入0.1 克 methylammonium 卤化物。为防止化学制品粘附在试管壁上, 使用称重纸筒将 methylammonium 卤化物转移到试管中. 
		注: 在 CH 3 NH 3 PbI 3-x br x 中, i/(i + br) 的最终比率由测试管中的 methylammonium 卤化物组成确定。例如, 为了达到 30% I 的内容, Schlenk 管加载了 0.03 g ch 3 NH 3 I 和 0.07 g ch 3 nh 3 Br. 实际获得的成分可能会随着实验的设置而变化, 所以合成条件的校准产生特定的靶成分是必要的。在本例中, 这是通过通过能量色散 X 射线光谱 (EDX) 测量合成薄膜中的卤化物含量来实现的. </li>
		<li> 使用装有旋转泵的 Schlenk 线连接和疏散管道。将压力调整到0.185 乇。然后, 把试管浸入硅油浴预热到120和 #176; C, 用磁力搅拌器 (600 rpm) 为 2 h (预处理 Schlenk 管). 
		注意: 这一步允许 methylammonium 前驱体沿 Schlenk 管的两侧升华。重要的是要确保 methylammonium 前体的升华在两个小时的预处理。一层薄薄的 methylammonium 前驱体将沿 Schlenk 管的两侧凝结, 以覆盖管的下半部。如果 methylammonium 前驱体的升华未被观察或发生得太快, 检查 Schlenk 线的压力和油浴的温度是否正确, 或尝试使用新鲜的 methylammonium 卤化物前驱物. #160; </li> <li> 删除 Schlenk管从油浴和离开 methylammonium 卤化物下的超压流动 N 2 , 以避免水分摄入. </li>
	</ol> </li> <li> 衬底准备 <ol> <li> 几种一个衬底 (玻璃或 FTO 镀膜玻璃, 14 x 16 mm 2 ), 含水 (〜3毫升) 含有洗涤剂为 15 min 在试管 (直径 1.5 cm 和高度 15 cm) 在35赫. </li>
		<li> 用超纯水 (10 毫升) 冲洗5次, 将洗涤剂/水丢弃. </li>
		<li> 丢弃超纯水, 加入丙酮 (〜3毫升), 几种为15分钟, 35 赫. </li>
		<li> 丢弃丙酮, 加入异丙醇 (〜3毫升), 并几种15分钟, 在35赫. </li>
		<li> 丢弃异丙醇, 用镊子从试管中回收基体, 并用 N 2 十五年代枪将其烘干. </li>
		<li> 沉积在 FTO 玻璃基底上的 2 致密层 (100 nm), 电子束蒸发在基底温度为350和 #176; C, 沉积速率为0.5 和 #197;/s 使用衬底旋转。 21 </li> </ol> </li> <li> 准备 MAPbI 3-x <ol> Brx (0 和 #60; x 和 #60; 3), 溶解 PbI <li> 2 (0.8 摩尔, 0.369 g) 和 PbBr 2 (0.2 摩尔, 0.073 g) 在1毫升 DMF 中达到最后浓度0.8 米的 PbI 2 和 0.2 m 的 PbBr 2 。几种为5分钟, 在35赫完全溶解的前兆。
		<ol> <li> 用于制备纯碘或溴薄膜, 在0.8 毫升 DMF 中溶解 PbI 2 (1 摩尔、0.461 g) 或 PbBr 2 (0.294 摩尔, 1 g), 分别达到 1 m 和 0.8 m 的最终浓度。几种为5分钟, 在35赫完全溶解前体. </li>
			<li> 用于制备掺氯的 methylammonium 铅钙钛矿薄膜, 溶解 PbI 2 (0.369 g) 和 PbCl 2 (0.056 g) 在1毫升 DMF 中, 以达到 PbI 0.8 m 的最终浓度, PbCl 2 和 0.2 m 的。几种为5分钟, 在35赫完全溶解前体. </li>
		</ol> </li> <li> 使用0.2 和 #956; m 聚四氟乙烯 (PTFE) 过滤器筛选前体解决方案. </li>
	</ol> </li> <li> 引线卤化物沉积 <ol> <li> 热板上的前体溶液设置为110和 #176; C 为 5 min. </li>
		<li> 带微, 下落80和 #956; 预热铅卤化物前驱体溶液到旋转基板上 (玻璃或镀膜 2 沉积在 FTO 涂层玻璃上; 14 x 16 mm 2 大小)。旋转在 500 rpm 为 5 s, 加速率为 500 rpm s -1 , 和 1500 rpm 为3分钟的 accelerati1500 rpm s -1 的速率. </li>
		<li> 在通风橱, 干燥前体膜为15分钟, 在110和 #176; C 在热板上流动 N 2 . 
		注: 使用 crystalizing 盘并放置在基板上, 以使前驱体在 N 2 大气中干燥。为了改变所产生的钙钛矿膜的厚度, 第二自旋涂层步骤的速度可从1200到 1.2万 rpm 不等, 以达到500至 100 nm 范围内的薄膜厚度。为进一步降低薄膜厚度, 可采用稀释前体溶液. </li>
	</ol> </li> <li> 蒸气辅助退火 <ol> <li> 将样品装入 Schlenk 管 (根据2.1.2 节的说明编写)。将压力调整到0.185 乇. 
		注: 样品位于 methylammonium 卤化物上方的试管中, 不与它直接接触。为了减缓 methylammonium 的合并, 铅卤化物表面是面向远离 methylammonium 卤化物. </li>
		<li> 将装有试样的 Schlenk 管浸入加热到120和 #176 的硅油浴中; C 为 2 h. </li>
		<li> 取出样品, 并将其浸入含有异丙醇的烧杯中快速冲洗。立即用 N 个 2 枪擦干冲洗过的样品. 
		注: 要准备纯 CH 3 NH 3 PbI 3 使用 PbI 2 作为卤化前驱体和纯 methylammonium 碘化物在蒸气辅助退火步骤中。要准备 CH 3 NH 3 PbBr 3 使用 PbBr 2 作为卤化物前驱体, 并在蒸气辅助退火步骤中采用纯 methylammonium 溴化物. </li>
	</ol>
	</li>
</ol>

<ol>
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作者没有什么可透露的。

为了制备高效的有机铅平面钙钛矿异, 活性层的均匀性是一个关键的要求。对于现有的解决方案2、16、17和 vacuum-based18、19方法, 我们的过程非常适合于可以综合在全 CH3NH3PbI3 xBrx组成空间, 具有高光电质量和重现性。6,<sup class=...

混合有机-无机铅卤化物 perovskites (CH3NH3PbX3, X = I, Br, Cl) 是一种新的半导体类, 在过去几年中迅速涌现。该材料类显示了优异的半导体性能, 如高吸收系数1、可调谐带隙的2、长电荷载流子扩散长度3、高缺陷容差4和高光致发光量子屈服5,6。这些特性的独特组合使得卤化铅 perovskites 在光电器件中具有很好的应用前景, 如单结点7、8和面光伏9, 10、激光器11、12和指示灯13。
CH3NH3PbX3胶片可由各种合成方法制作而成14, 其目的是提高这一半导体材料的能量应用效率15。然而, 光伏器件的优化依赖于卤化钙钛矿活性层的质量, 以及它与电荷选择性接触 (即电子和空穴传输层) 的界面, 从而促进了这些载波的收集。设备.具体来说, 连续的, 无针孔的主动层是必要的, 以减少分流电阻, 从而提高设备的性能。
在制备有机铅卤化物钙钛矿薄膜的最广泛的方法是解决和 vacuum-based 过程。最常见的解决方法是使用在胺 (DMF)、砜 (亚砜) 或γ-丁内 (GBL) 或这些溶剂的混合物中溶解的卤化铅和 methylammonium 卤化物的摩尔比值。2,16,17前体浓度和溶剂型, 以及退火温度、时间和大气, 必须精确控制以获得连续和无针孔薄膜。16例如, 为了提高表面覆盖度, 我们展示了一种溶剂工程技术, 以产生致密和极均匀的薄膜。17在这种技术中, 在钙钛矿溶液的纺丝过程中, 溶剂 (甲苯) 滴在钙钛矿层上。17这些方法通常很适合介观异, 它采用了介孔的.2作为与增加接触面积和减少载流子传输长度的电子选择性接触。
然而, 平面异, 使用选择性接触的基础上薄 (通常为2) 电影, 更可取的, 因为它们提供了一个简单的和可伸缩的配置, 可以更容易地采用太阳能电池技术。因此, 在平面异的作用下, 开发出具有高效、稳定的有机铅卤化物钙钛矿活性层, 可能会导致该领域的技术进步。然而, 制造平面异的主要挑战之一仍然是由活性层的均匀性所代表。一些尝试, 根据真空的过程, 已作出准备均匀层在薄的2电影。例如, Snaith 和合作者已经证明了双蒸发过程, 它产生高度均匀的钙钛矿层, 高功率转换效率的光伏应用。18虽然这项工作代表了该领域的一个重大进展, 但使用高真空系统和缺乏调谐的组成的活性层限制了该方法的适用性。有趣的是, 通过蒸气辅助解决方案 (VASP)19和修改后的低压 VASP (LP-VASP)620, 实现了极高的一致性。虽然 VASP, 由杨和合作者建议的19, 需要更高的温度和使用一个手套箱, LP-VASP 是基于在 methylammonium 卤化物蒸气存在的铅卤化物前驱层的退火, 在减少压力和通风橱的温度相对较低。这些特定的条件使接入混合钙钛矿组成, 并制作纯 CH3nh3PbI3, ch3nh3PbI3 xClx, ch3nh3PbI3可以轻松实现 x Brx和 CH3NH3PbBr3 。具体地说, CH3NH3PbI3-xBrx胶片在整个合成空间上可以合成高光电质量和再现性6,20。
本文详细介绍了通过 LP VASP 合成有机-无机卤化铅钙钛矿层的协议, 其中包括合成 methylammonium 卤化物前驱体的程序。一旦合成了前驱体, CH3NH3PbX3胶片的形成包括 i 的 two-step 过程) PbI2/PbBr2 (PbI2或 PbI2/PbCl 的自旋涂层2) 在玻璃衬底或掺氟锡氧化物 (FTO) 涂层玻璃基板上的前驱物, 其平面上有2, 作为电子传输层, ii) 在 CH3NH3I 的混合物中进行低压蒸气辅助退火CH3NH3Br 可根据所需的光学带隙 (1.6 ev ≤ Eg ≤ 2.3 ev) 进行微调。在这些条件下, 在气相中的 methylammonium 卤化物分子慢慢扩散到卤化铅薄膜中, 产生连续的无针孔卤化物钙钛矿膜。这一过程产生两倍的体积扩展从开始的卤化铅前驱层到完成有机-无机卤化铅钙钛矿。钙钛矿薄膜的标准厚度约 400 nm。通过改变第二个自旋涂层的速度, 可以在100-500 纳米之间变化这一厚度。该技术的结果, 在高光电质量的薄膜, 它转化为光伏设备的功率转换效率高达19% 使用一个 Au/螺 OMeTAD/CH3NH3PbI3-xBrx紧凑的2/FTO/玻璃太阳电池结构。21

<table><tbody><tr><td>Lead (II) bromide, 99.999%</td><td>Sigma-Aldrich</td><td>398853</td><td>Acute toxicity, Carcinogenicity</td></tr><tr><td>Lead (II) Iodide, 99.9985%</td><td>Alfa Aesar</td><td>12724</td><td>Acute toxicity, light sensitive</td></tr><tr><td>N, N-Dimethylformamide, &gt; 99.9%</td><td>Sigma-Aldrich</td><td>270547</td><td>Acute toxicity, flamable; store in well ventilated place</td></tr><tr><td>Isopropyl alcohol, 99.5%</td><td>BDH</td><td>BDH1133-4LP</td><td>Flamable</td></tr><tr><td>Methylamine ca. 40% in water</td><td>TCI</td><td>M0137</td><td>Acute toxicity, flamable; Corrosive</td></tr><tr><td>Hydrobromic acid 48 wt. % in H2O, &amp;ge;99.99%</td><td>Sigma-Aldrich</td><td>339245</td><td>Acute toxicity, Corrosive; air and light sensitive; store in well ventilated place</td></tr><tr><td>Hydroiodic acid 57 wt. % in H2O, distilled, stabilized, 99.95%</td><td>Sigma-Aldrich</td><td>210021</td><td>Corrosive; air and light sensitive; store in well ventilated place&lt;br/&gt; Recommended storage temperature 2/8 &amp;deg;C; air and light sensitiv</td></tr><tr><td>Ethyl Ether Anhydrous BHT Stabilized/Certified ACS</td><td>Fisher Chemicals</td><td>E 138-4</td><td>Acute toxicity, flamable</td></tr><tr><td>Ethanol Denatured (Reagent Alcohol), ACS</td><td>BDH</td><td>BDH1156-4LP</td><td>Flamable</td></tr><tr><td>Alconoxdetergent</td><td>Sigma-Aldrich</td><td>242985</td><td>Soap utilized for substrate cleaning</td></tr><tr><td>Milli-QIntegral 3 Water Purification System</td><td>EMD Millipore</td><td>ZRXQ003WW</td><td>Dispenser of ultrapure water</td></tr><tr><td>Fluorine-doped Thin Oxide (FTO) coated glass</td><td>Thin Film Devices</td><td>Custom</td><td>Glass: dimensions 13.8mm x 15.8mm &amp;plusmn; 0.2mm, thickness 2.3mm &amp;plusmn; 0.1mm; FTO: dimensions 3000&amp;Aring; &amp;plusmn; 100&amp;Aring;, resistivity 7-10 ohms/sq, transmission 82% @ 550nm)</td></tr><tr><td>Glass substrates</td><td>C &amp;amp; A Scientific - Premiere</td><td>9101-E</td><td>Plain. Length: 75 mm, Width: 25 mm, Thickness: 1 mm</td></tr><tr><td>Ultrasonic Cleaner with Digital Timer and Heater</td><td>VWR</td><td>97043-992</td><td>2.8 L (0.7 gal.)24L x 14W x 10D cm (97/16x 51/2x 315/16&quot;)</td></tr><tr><td>Nuclear Magnetic Resonance Advance 500</td><td>Bruker</td><td>Z115311</td><td></td></tr><tr><td>Quanta 250 FEG Scanning Electron Microscope</td><td>FEI</td><td>743202032141</td><td>Equipped with a Bruker Xflash 5030 Energy-dispersive X-ray detector</td></tr><tr><td>SmartLab X-ray diffractometer</td><td>Rigaku</td><td>2080B411</td><td>Using Cu K&amp;alpha; radiation at 40 kV and 40 mA</td></tr></tbody></table>

low pressure vapor-assisted solution process for tunable band gap pinhole-free methylammonium lead halide perovskite films

有机铅卤化物 perovskites 最近引起了人们对薄膜光电和光电子的潜在应用的极大兴趣。本文通过低压蒸气辅助溶液 (LP-VASP) 法, 提出了一种在平面质钙钛矿太阳能电池中产生19% 功率转换效率的协议。首先, 我们报告的合成 methylammonium 碘化物 (ch3nh3I) 和 methylammonium 溴 (ch3nh3Br) 从甲胺和相应的卤化物酸 (HI 或评论)。然后, 我们描述的制造无针孔, 连续 methylammonium 铅卤化物钙钛矿 (CH3NH3PbX3与 X = I, Br, Cl 和他们的混合物) 影片与 LP-VASP。此过程基于两个步骤: i) 将卤化铅前驱体的同质层的自旋涂覆到基板上, ii) 将此层转换为 ch3NH3PbI3-xBrx , 将基底暴露在混合 ch 的蒸气中3nh3I 和 CH3nh3Br 在减压和120° c。通过缓慢扩散的 methylammonium 卤化物蒸汽进入铅卤化物前驱体, 我们实现了缓慢和控制生长的连续, 无针孔的钙钛矿薄膜。LP VASP 允许在 CH3NH3PbI3-xBrx中以0≤ x ≤3对完整的卤化物合成空间进行综合访问。根据气相的组成, 带隙可以调谐 1.6 ev ≤ Eg ≤ 2.3 ev。此外, 通过改变卤化物前驱体和气相的组成, 我们还可以获得 CH3NH3PbI3 xClx。从 LP VASP 获得的薄膜具有重现性, 经 X 射线衍射测定证实的相纯度, 具有高光致发光量子产率。该过程不需要使用手套。

质子核磁共振 (NMR) 光谱后, methylammonium 卤化物合成验证分子纯度 (图 1)。在蒸气退火 (图 2) 之前和之后获得扫描电子显微镜 (SEM) 图像, 以表征混合铅卤化物前驱体和 CH3NH3PbI3 xBrx 的形貌和均匀性影片。收集 x 射线衍射 (XRD) 模式, 以确定相纯度和转换的铅卤化物到 CH3NH3PbI3-x...

Watch this Scientific Journal Video about Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films at JoVE.com

Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films

在这里, 我们提出了一个协议的合成 CH3nh3I 和 ch3nh3Br 前体和随后形成无针孔, 连续 CH3NH3PbI3 xBrx薄膜在高效太阳能电池等光电器件中的应用。

可调谐带隙无针孔 Methylammonium 铅卤化物钙钛矿薄膜的低压蒸气辅助解决工艺

Organo-lead halide perovskites have recently attracted great interest for potential applications in thin-film photovoltaics and optoelectronics. Herein, ...

low-pressure-vapor-assisted-solution-process-for-tunable-band-gap

Research

JoVE Journal

Chemistry

9.5K 次观看.  Lawrence Berkeley National Laboratory. 在这里, 我们提出了一个协议的合成 CH3nh3I 和 ch3nh3Br 前体和随后形成无针孔, 连续 CH3NH3PbI3 xBrx薄膜在高效太阳能电池等光电器件中的应用。

视频: Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films

Template Directed Synthesis of Plasmonic Gold Nanotubes with Tunable IR Absorbance

A nearly parallel array of pores can be produced by anodizing aluminum foils in acidic environments1, 2. Applications of anodic aluminum oxide (AAO) membranes have been under development since the 1990's and have become a common method to template the synthesis of high aspect ratio nanostructures, mostly by electrochemical growth or pore-wetting. Recently, these membranes have become commercially available in a wide range of pore sizes and densities, leading to an extensive library of functional nanostructures being synthesized from AAO membranes. These include composite nanorods, nanowires and nanotubes made of metals, inorganic materials or polymers 3-10. Nanoporous membranes have been used to synthesize nanoparticle and nanotube arrays that perform well as refractive index sensors, plasmonic biosensors, or surface enhanced Raman spectroscopy (SERS) substrates 11-16, as well as a wide range of other fields such as photo-thermal heating 17, permselective transport 18, 19, catalysis 20, microfluidics 21, and electrochemical sensing 22, 23. Here, we report a novel procedure to prepare gold nanotubes in AAO membranes. Hollow nanostructures have potential application in plasmonic and SERS sensing, and we anticipate these gold nanotubes will allow for high sensitivity and strong plasmon signals, arising from decreased material dampening 15.

Solution-suspendable gold nanotubes with controlled dimensions can be synthesized by electrochemical deposition in porous anodic aluminum oxide (AAO) membranes using a hydrophobic polymer core. Gold nanotubes and nanotube arrays hold promise for applications in plasmonic biosensing, surface-enhanced Raman spectroscopy, photo-thermal heating, ionic and molecular transport, microfluidics, catalysis and electrochemical sensing.

的模板导演电浆黄金纳米管的合成与可调谐红外吸收

A nearly parallel array of pores can be produced by anodizing aluminum foils in acidic environments1, 2. Applications of anodic aluminum oxide (AAO) ...

科研

化学

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal inks. For the photoactive absorber layer, colloidal CdTe and CdSe nanocrystals (3-5 nm) are synthesized using an inert hot injection technique and cleaned with precipitations to remove excess starting reagents. Similarly, gold nanocrystals (3-5 nm) are synthesized under ambient conditions and dissolved in organic solvents. In addition, precursor solutions for transparent conductive indium tin oxide (ITO) films are prepared from solutions of indium and tin salts paired with a reactive oxidizer. Layer-by-layer, these solutions are deposited onto a glass substrate following annealing (200-400 &#176;C) to build the nanocrystal solar cell (glass/ITO/CdSe/CdTe/Au). Pre-annealing ligand exchange is required for CdSe and CdTe nanocrystals where films are dipped in NH4Cl:methanol to replace long-chain native ligands with small inorganic Cl- anions. NH4Cl(s) was found to act as a catalyst for the sintering reaction (as a non-toxic alternative to the conventional CdCl2(s) treatment) leading to grain growth (136&#177;39 nm) during heating. The thickness and roughness of the prepared films are characterized with SEM and optical profilometry. FTIR is used to determine the degree of ligand exchange prior to sintering, and XRD is used to verify the crystallinity and phase of each material. UV/Vis spectra show high visible light transmission through the ITO layer and a red shift in the absorbance of the cadmium chalcogenide nanocrystals after thermal annealing. Current-voltage curves of completed devices are measured under simulated one sun illumination. Small differences in deposition techniques and reagents employed during ligand exchange have been shown to have a profound influence on the device properties. Here, we examine the effects of chemical (sintering and ligand exchange agents) and physical treatments (solution concentration, spray-pressure, annealing time and annealing temperature) on photovoltaic device performance.

This protocol describes the synthesis and solution deposition of inorganic nanocrystals layer by layer to produce thin film electronics on non-conductive surfaces. Solvent-stabilized inks can produce complete photovoltaic devices on glass substrates via spin and spray coating following post-deposition ligand exchange and sintering.

全面解决方案处理的无机纳米晶体光伏器件的制造

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal ...

工程学

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

上成膜钙钛矿型混合制造方法，电子结构和太阳能电池性能的影响

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...

Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials such as organo-lead halide perovskites is presented. The perovskite film thickness and absorption coefficient are initially characterized by profilometry and UV-VIS absorption spectroscopy. Calibration of both laser power and cavity sensitivity is described in detail. A protocol for performing Flash-photolysis Time Resolved Microwave Conductivity (TRMC) experiments, a non-contact method of determining the conductivity of a material, is presented. A process for identifying the real and imaginary components of the complex conductivity by performing TRMC as a function of microwave frequency is given. Charge carrier dynamics are determined under different excitation regimes (including both power and wavelength). Techniques for distinguishing between direct and trap-mediated decay processes are presented and discussed. Results are modelled and interpreted with reference to a general kinetic model of photoinduced charge carriers in a semiconductor. The techniques described are applicable to a wide range of optoelectronic materials, including organic and inorganic photovoltaic materials, nanoparticles, and conducting/semiconducting thin films.

A Time Resolved Microwave Conductivity technique for investigating direct and trap-mediated recombination dynamics and determining carrier mobilities of thin film semiconductors is presented here.

通过时间分辨微波电导率重组动力学薄膜光伏材料

A method for investigating recombination dynamics of photo-induced charge carriers in thin film semiconductors, specifically in photovoltaic materials ...

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with similar ionic radii to Pb2+, including Cu+, Na+, and Ag+. A shift in the Fermi level and a remarkable decrease of sub-bandgap optical absorption, along with a lower energetic disorder in the perovskite, was achieved. An order-of-magnitude enhancement in the bulk hole mobility and a significant reduction of transport activation energy within an additive-based perovskite device was attained. The confluence of the aforementioned improved properties in the presence of these cations led to an enhancement in the photovoltaic parameters of the perovskite solar cell. An increase of 70 mV in open circuit voltage for AgI and a 2 mA/cm2 improvement in photocurrent density for NaI- and CuBr-based solar cells were achieved compared to the pristine device. Our work paves the way for further improvements in the optoelectronic quality of CH3NH3PbI3 perovskite and subsequent devices. It highlights a new avenue for investigations on the role of dopant impurities in crystallization and controls the electronic defect density in perovskite structures.

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we present a protocol to adjust the properties of solution-processed CH3NH3PbI3 through the incorporation of monovalent cation additives in order to achieve highly efficient perovskite solar cells.

CH的单价阳离子兴奋剂<sub&gt; 3</sub&gt; NH<sub&gt; 3</sub&gt;碘化铅<sub&gt; 3</sub&gt;对钙钛矿型高效太阳能电池

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical ...

Flash Infrared Annealing for Perovskite Solar Cell Processing

Organic&#8211;inorganic perovskites have an impressive potential for the design of next generation solar cells and are currently considered for upscaling and commercialization. Currently, perovskite solar cells rely on spin-coating which is neither practical for large areas nor environmentally friendly. Indeed, one of the conventional and most effective lab-scale methods to induce perovskite crystallization, the antisolvent method, requires an amount of toxic solvent that is difficult to apply on larger surfaces. To solve this problem, an antisolvent-free and rapid thermal annealing process called flash infrared annealing (FIRA) can be used to produce highly crystalline perovskite films. The FIRA oven is composed of an array of near-infrared halogen lamps with an illumination power of 3,000 kW/m2. A hollow aluminum body enables an effective water-cooling system. The FIRA method allows the synthesis of perovskite films in less than 2 s, achieving efficiencies &#62;20%. FIRA has a unique potential for the industry because it can be adapted to continuous processing, is antisolvent-free, and does not require lengthy, hour-long annealing steps.

We describe a flash infrared annealing method used for the synthesis of perovskite and mesoscopic-TiO2 films. Annealing parameters are varied and optimized for processing on fluorine-doped tin oxide (FTO) glass and indium tin oxide-coated polyethylene terephthalate (ITO PET), subsequently giving devices power conversion efficiencies &#62;20%.

用于佩罗夫斯基特太阳能电池处理的闪光红外退火

Organic&#8211;inorganic perovskites have an impressive potential for the design of next generation solar cells and are currently considered for upscaling ...

环境科学

A Modular Microfluidic Technology for Systematic Studies of Colloidal Semiconductor Nanocrystals

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are a rapidly growing class of materials in commercial electronics, such as light emitting diodes (LEDs) and photovoltaics (PVs). Among this material group, inorganic/organic perovskites have demonstrated significant improvement and potential towards high-efficiency, low-cost PV fabrication due to their high charge carrier mobilities and lifetimes. Despite the opportunities for perovskite QDs in large-scale PV and LED applications, the lack of fundamental and comprehensive understanding of their growth pathways has inhibited their adaptation within continuous nanomanufacturing strategies. Traditional flask-based screening approaches are generally expensive, labor-intensive, and imprecise for effectively characterizing the broad parameter space and synthesis variety relevant to colloidal QD reactions. In this work, a fully autonomous microfluidic platform is developed to systematically study the large parameter space associated with the colloidal synthesis of nanocrystals in a continuous flow format. Through the application of a novel translating three-port flow cell and modular reactor extension units, the system may rapidly collect fluorescence and absorption spectra across reactor lengths ranging 3 - 196 cm. The adjustable reactor length not only decouples the residence time from the velocity-dependent mass transfer, it also substantially improves the sampling rates and chemical consumption due to the characterization of 40 unique spectra within a single equilibrated system. Sample rates may reach up to 30,000 unique spectra per day, and the conditions cover 4 orders of magnitude in residence times ranging 100 ms - 17 min. Further applications of this system would substantially improve the rate and precision of the material discovery and screening in future studies. Detailed within this report are the system materials and assembly protocols with a general description of the automated sampling software and offline data processing.

Detailed herein are the operation and assembly protocols of a modular microfluidic screening platform for the systematic characterization of colloidal semiconductor nanocrystal syntheses. Through fully adjustable system arrangements, highly efficient spectra collection may be carried out across 4 orders of magnitude reaction time scales within a mass transfer-controlled sampling space.

胶体半导体纳米晶系统研究的模块化微流控技术

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are a rapidly growing class of materials in commercial electronics, such as light ...

Solution-Processed "Silver-Bismuth-Iodine" Ternary Thin Films for Lead-Free Photovoltaic Absorbers

Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. However, poor surface morphologies and relatively high bandgap energies have limited their potential. Silver-bismuth-iodine (Ag-Bi-I) is a promising semiconductor for optoelectronic devices. Therefore, we demonstrate the fabrication of Ag-Bi-I ternary thin films using material solution processing. The resulting thin films exhibit controlled surface morphologies and optical bandgaps according to their thermal annealing temperatures. In addition, it has been reported that Ag-Bi-I ternary systems crystallize to AgBi2I7, Ag2BiI5, etc. according to the ratio of the precursor chemicals. The solution-processed AgBi2I7 thin films exhibit a cubic-phase crystal structure, dense, pinhole-free surface morphologies with grains ranging in size from 200 to 800 nm, and an indirect bandgap of 1.87 eV. The resultant AgBi2I7 thin films show good air stability and energy band diagrams, as well as surface morphologies and optical bandgaps suitable for lead-free and air-stable single-junction solar cells. Very recently, a solar cell with 4.3% power conversion efficiency was obtained by optimizing the Ag-Bi-I crystal compositions and solar cell device architectures.

Herein, we present detailed protocols for solution-processed silver-bismuth-iodine (Ag-Bi-I) ternary semiconductor thin films fabricated on TiO2-coated transparent electrodes and their potential application as air-stable and lead-free optoelectronic devices.

无铅光伏吸收剂的溶液处理 "银铋碘" 三元薄膜

Bismuth-based hybrid perovskites are regarded as promising photo-active semiconductors for environment-friendly and air-stable solar cell applications. ...

Inkjet Printing All Inorganic Halide Perovskite Inks for Photovoltaic Applications

A method for synthesizing photoactive inorganic&#160;perovskite quantum dot inks and an inkjet printer deposition method, using the synthesized inks, are demonstrated. The ink synthesis is based on a simple wet chemical reaction and the inkjet printing protocol is a facile step by step method. The inkjet printed thin films have been characterized by X-ray diffraction, optical absorption spectroscopy, photoluminescent spectroscopy, and electronic transport measurements. X-ray diffraction of the printed quantum dot films indicates a crystal structure consistent with an orthorhombic room temperature phase with (001) orientation. In conjunction with other characterization methods, the X-ray diffraction&#160;measurements show high quality films can be obtained through the inkjet printing method.

A protocol for synthesizing inorganic-lead-halide hybrid perovskite quantum dot inks for inkjet printing and the protocol for preparing and printing the quantum dot inks in an inkjet printer with post characterization techniques are presented.

用于光伏应用的喷墨打印所有无机舱齐德 perovskite 油墨

A method for synthesizing photoactive inorganic&#160;perovskite quantum dot inks and an inkjet printer deposition method, using the synthesized inks, are ...

Facile Synthesis of Colloidal Lead Halide Perovskite Nanoplatelets via Ligand-Assisted Reprecipitation

In this work, we demonstrate a facile method for colloidal lead halide perovskite nanoplatelet synthesis (Chemical formula: L2[ABX3]n-1BX4, L: butylammonium and octylammonium, A: methylammonium or formamidinium, B: lead, X: bromide and iodide, n: number of [BX6]4- octahedral layers in the direction of nanoplatelet thickness) via ligand-assisted reprecipitation. Individual perovskite precursor solutions are prepared by dissolving each nanoplatelet constituent salt in N,N-dimethylformamide (DMF), which is a polar organic solvent, and then mixing in specific ratios for targeted nanoplatelet thickness and composition. Once the mixed precursor solution is dropped into nonpolar toluene, the abrupt change in the solubility induces the instantaneous crystallization of nanoplatelets with surface-bound alkylammonium halide ligands providing colloidal stability. Photoluminescence and absorption spectra reveal emissive and strongly quantum-confined features. X-ray diffraction and transmission electron microscopy confirm the two-dimensional structure of the nanoplatelets. Furthermore, we demonstrate that the band gap of perovskite nanoplatelets can be continuously tuned in the visible range by varying the stoichiometry of the halide ion(s). Lastly, we demonstrate the flexibility of the ligand-assisted reprecipitation method by introducing multiple species as surface-capping ligands. This methodology represents a simple procedure for preparing dispersions of emissive 2D colloidal semiconductors.

This work demonstrates facile room-temperature synthesis of colloidal quantum-confined lead halide perovskite nanoplatelets by ligand-assisted reprecipitation method. Synthesized nanoplatelets show spectrally narrow optical features and continuous spectral tunability throughout the visible range by varying the composition and thicknesses.

可调谐带隙无针孔 Methylammonium 铅卤化物钙钛矿薄膜的低压蒸气辅助解决工艺

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