Kattoor Vidya, Awasthi Kamlesh, Jokar Efat, Diau Eric Wei-Guang, Ohta Nobuhiro
Department of Applied Chemistry and Institute of Molecular Science , National Chiao Tung University , 1001 Ta-Hsueh Road , Hsinchu 30010 , Taiwan.
Sustainable Chemical Science and Technology (SCST) , Taiwan International Graduate Program (TIGP), Academia Sinica , Nankang, Taipei 115 , Taiwan.
J Phys Chem Lett. 2019 Aug 15;10(16):4752-4757. doi: 10.1021/acs.jpclett.9b01759. Epub 2019 Aug 7.
The dependence of photoluminescence (PL) on excitation power and the effect of an external electric field have been studied for a two-dimensional (2D) perovskite (CHNH)PbI thin-film sample. The efficiency of dissociation of hot excitons to produce free carriers was enhanced with a small excitation power because the relaxation of hot excitons to cold emissive excitons was slow, indicating that the thermal energies of hot carriers can be utilized in solar cells under weak photoirradiation. The dissociation was notably enhanced with an applied electric field, resulting in efficient field-induced quenching of the PL. The present results shed light on an application of 2D perovskite materials to photovoltaic (PV) devices with dim radiation, e.g., for indoor PV applications; the concept of electric field-assisted solar cells might be applicable to next-generation solar cells.
针对二维（2D）钙钛矿（CHNH）PbI薄膜样品，研究了光致发光（PL）对激发功率的依赖性以及外部电场的影响。由于热激子向冷发射激子的弛豫较慢，在低激发功率下热激子解离产生自由载流子的效率得以提高，这表明在弱光照射下太阳能电池中热载流子的热能可被利用。施加电场时，解离显著增强，导致PL的有效场致猝灭。本研究结果为二维钙钛矿材料在低辐射光伏（PV）器件中的应用提供了思路，例如用于室内PV应用；电场辅助太阳能电池的概念可能适用于下一代太阳能电池。
