Perovskite Solar Cells have high photoelectric conversion efficiency (> 22.7%), which is considered by researchers to be one of the most promising ways to solve energy problems in recent years. However, the stability of conventional organic-inorganic hybrid perovskite light absorbing materials has become the biggest obstacle to its commercialization. To this end, the researchers tried to develop a new type of perovskite structure light absorber. Among them, CsPbBr3 with perovskite structure exhibits excellent optical, thermal and chemical stability, and is an ideal battery material. At present, the battery efficiency has been improved to more than 13% through technical optimization and interface optimization. However, there are still some problems in this type of battery: First, the traditional titanium dioxide electron transport layer not only requires a higher calcination temperature, but is not conducive to the preparation of flexible devices, and it will have severe degradation of perovskite materials under ultraviolet light irradiation conditions. Secondly, the presence of hygroscopic additives in the currently used hole transport layer also reduces the stability of the battery, increases the production cost, and does not utilize the commercialization process of the battery. Therefore, how to improve the preparation process of CsPbBr3 inorganic perovskite solar cells, reduce the preparation temperature and production cost is one of the urgent problems to be solved.

Summary of results

Recently, Professor Tang Qunwei from Jinan University's New Energy Technology Research Institute (communication author) constructed a simplified inorganic perovskite battery device whose basic structure is FTO/CsPbBr3/Carbon. The researchers avoided the use of the traditional electron transport layer and the hole transport layer, simplifying the structure and preparation process of the battery, while the battery device of the structure obtained 2.35% photoelectric conversion efficiency under standard light intensity. Compared with the traditional battery structure, the performance of the device is low, and the main reason can be summarized as: the energy level difference between the interfaces is large, and the charge extraction ability is weak, resulting in serious interface charge recombination phenomenon. To this end, the researchers further used graphene quantum dots and CsPbBrI2 perovskite quantum dots for interface modification, which increased the battery efficiency to 4.1%. The related results are published in Small magazine under the title "Simplified Perovskite Solar Cell with 4.1%-Efficiency Employing Inorganic CsPbBr3 as Light Absorber".

Graphic introduction

Figure 1. Assembly process of battery devices and related characterization

(a) a preparation process of CsPbBr3;

(b) surface topography of PbBr2 and CsPbBr3 films;

(c) SEM sectional view and energy level diagram of the inorganic perovskite battery;

(d) an ultraviolet absorption curve of CsPbBr3;

(e) Band gap calculation of CsPbBr3;

(f) an XRD pattern of CsPbBr3;

Figure 2 Photovoltaic performance characterization of battery devices

(a) J-V curves for different cell structures;

(b) IPCE curves for different cell structures;

(c) Steady-state output curves for different battery configurations;

(d) the efficiency distribution of the battery;

Figure 3 electronic composite characterization

(a) Steady-state PL test of perovskite film before and after quantum dot modification;

(b) Time-resolved fluorescence spectra of perovskite films before and after quantum dot modification;

(c) a relationship between the short-circuit current density and the light intensity;

(d) the relationship between the open circuit voltage and the light intensity;

Figure 4 battery stability performance