Formamidinium lead triiodide quantum dot (FAPbI3 QD) exhibits substantial potential in solar cells due to its suitable band gap, extended carrier lifetime, and superior phase stability. However, despite great attempts toward reconfiguring the surface chemical environment of FAPbI3 QDs, achieving the optimal efficiency of charge carrier extraction and transfer in cells remains a challenge. To circumvent this problem, we selectively introduced Au/FAPbI3 Schottky heterojunctions by reducing Au+ to Au0 and subsequently anchoring them on the surface of FAPbI3 QDs, which acts as a light-harvesting layer and establishes high-speed electron transfer channels (Au dot ↔ Au dot). As a result, the champion photoelectric conversion efficiency of solar cells reached 13.68%, a significant improvement over 11.19% of that of FAPbI3-based solar cells. The enhancement is attributed to efficient and directed electron transfer as well as a more aligned energy level arrangement. This work constructed Au/FAPbI3 QD Schottky heterojunctions, providing a viable strategy to enhance QD electron coupling for high-performance optoelectronic applications.
Yucheng Liu,Jiankun Sun,Zhou Yang,Dong Yang,Xiaodong Ren,Hua Xu,Zupei Yang,Shengzhong (Frank) Liu
CH 3 NH 3 PbX 3 (MAPbX 3 )-based perovskite has attracted tremendous research efforts in the last few years. With the discovery that the HC(NH 2 ) 2 PbI 3 (FAPbI 3 ) perovskite offers even higher solar cell efficiency, better thermal stability, and broader optical absorption, it is expected that it will provide more excitement in optoelectronic applications including laser, LED, photodetector, etc. The development in preparing large Single-Crystalline Formamidinium-Perovskite FAPbI 3 using the inverse-temperature reactive crystallization process, and associated wafer-slicing process is presented. The availability of the large Single-Crystalline Formamidinium-Perovskite Wafer makes it possible to fabricate integrated circuits. An array of 153 photodetectors on a piece of thin wafer, demonstrating feasibility of mass production of integrated circuits on the perovskite wafer is designed and prepared. It is found that the wafer-based photodetector shows much superior performance, with 90 times higher photoresponse and broader optical absorption than its thin-film perovskite counterpart.
Rong Li,Jiale Ding,Xijiao Mu,Yifei Kang,Anran Wang,Weihui Bi,Yunhe Zhang,Jing Cao,Qingfeng Dong
The extreme instability of pure α-phase FAPbI 3 under high humidity conditions restricts the high-throughput fabrication in unmodified air environments, resulting in poor performance of α-phase FAPbI 3 perovskite devices obtained by scalable fabrication methods. Here we synthesized hyperbranched copper phthalocyanine (HCuPc) as a supramolecular additive with twisted phthalocyanine units to realize the molecular-level encapsulation at the grain boundaries through supramolecular interaction, which greatly broadened the processing window of FAPbI 3 under high humidity. At the same time, unlike traditional encapsulation layer that carrier can only be collected by tunneling effect, the twisted phthalocyanine ring of HCuPc in perovskite films is more conducive to hole extraction. Finally, a record efficiency was achieved in pure FAPbI 3 based inverted structured solar cell by blade-coating to the best of our knowledge, even under unmodified humid air conditions (relative humidity of 65%–85%). The best operational stability of 3D pure FAPbI 3 devices can also be achieved at the same time and unencapsulated HCuPc-FAPbI 3 device can even operate with negligible degradation for 100 h in the open air (RH 30%–40%).
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