enhanced-electron-injection-exciton-confinement-for-pure-blue-quantum

Enhanced Electron Injection and Exciton Confinement for Pure Blue Quantum-Dot Light-Emitting Diodes by Introducing Partially Oxidized Aluminum Cathode

Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation ...

North China Electric Power University

For bulk heterojunction polymer solar cells (PSCs), the donors and acceptors featuring specific phase separation and concentration distribution within the electron donor/acceptor blends crucially affect the exciton dissociation and charge transportation. Herein, efficient and stable nonfullerene inverted PSCs incorporating a phase separated photoactive layer and a titanium chelate electrode modification layer are demonstrated. Water contact angle (WCA), scanning kelvin probe microscopy (SKPM), and atomic force microscopy (AFM) techniques are implemented to characterize the morphology of photoactive layers. Compared with the control conventional device, the short-circuit current density (J) is enhanced from 14.74 to 17.45 mAcm. The power conversion efficiency (PCE) for the inverted PSCs with a titanium (diisopropoxide)-bis-(2,4-pentanedionate) (TIPD) layer increases from 9.67% to 11.69% benefiting from the declined exciton recombination and fairly enhanced charge transportation. Furthermore, the nonencapsulated inverted device with a TIPD layer demonstrates the best long-term stability, 85% of initial PCE remaining and an almost undecayed open-circuit voltage (V) after 1440 h. Our results reveal that the titanium chelate is an excellent electrode modification layer to incorporate with a vertical phase separated photoactive layer for producing high-efficiency and high-stability inverted nonfullerene PSCs.

Incorporating an Electrode Modification Layer with a Vertical Phase Separated Photoactive Layer for Efficient and Stable Inverted Nonfullerene Polymer Solar Cells.

Enhancing the light-harvesting activity is an effective way to improve the power conversion efficiency of solar cells. Although rapid enhancement in the PCE up to a value of 22.1% has been achieved for perovskite solar cells, only part of the sunlight, i.e., with wavelengths below 800-850 nm is utilized due to the limited bandgap of the perovskite materials, resulting in most of the near infrared light being wasted. To broaden the photoresponse of perovskite solar cells, we demonstrate an efficient perovskite/organic integrated solar cell containing both CHNHPbI perovskite and PBDTTT-E-T:IEICO organic photoactive layers. By integrating a low band gap PBDTTT-E-T:IEICO active layer on a perovskite layer, the maximum wavelength for light harvesting of the ISC increased to 930 nm, sharply increasing the utilization of near infrared radiation. In addition, the external quantum efficiency of the integrated device exceeded 50% in the near infrared range. The MAPbI/PBDTTT-E-T:IEICO ISCs show an enhanced short-circuit current density of over 24 mA cm, which is the highest existing value among perovskite/organic integrated solar cells and much higher than the traditional MAPbI based perovskite solar cells. The results reveal that a perovskite/organic integrated structure is a promising strategy to extend and enhance sunlight utilization for perovskite solar cells.

Efficient perovskite/organic integrated solar cells with extended photoresponse to 930 nm and enhanced near-infrared external quantum efficiency of over 50.

Xingming Bian

State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources

North China Electric Power University

Enhanced Electron Injection and Exciton Confinement for Pure Blue Quantum-Dot Light-Emitting Diodes by Introducing Partially Oxidized Aluminum Cathode