Herein we propose a new equivalent circuit including double heterojunctions in series to simulate the current–voltage characteristic of P–I–N planar structure perovskite solar cells. This new method can theoretically solve the dilemma of the parameter diode ideal factor being larger than2 from an ideal single heterojunction equivalent circuit,which usually is in the range from 1 to 2. The diode ideal factor reflects PN junction quality, which influences the recombination at electron transport layer/perovskite and perovskite/hole transport layer interface. Based on the double PN junction equivalent circuit, we can also simulate the dark current–voltage curve for analyzing recombination current(Shockley–Read–Hall recombination) and diffusion current(including direct recombination), and thus carrier recombination and transportation characteristics. This new model offers an efficacious and simple method to investigate interfaces condition, film quality of perovskite absorbing layer and performance of transport layer, helping us furtherimprove the device efficiency and analyze the working mechanism.
Peizhe LiaoXiaojuan ZhaoGuolong LiYan ShenMingkui Wang
In recent years perovskite solar cells have attracted an increasing scientific and technological interest in the scientific community. It is important to know that the temperature is one of the factors which have a strong effect on the efficiency of perovskite solar cell. This study communicates a temperature analysis on the photovoltaic parameters of CH_3NH_3PbI_3-based perovskite solar cell in a broad interval from 80 to 360 K. Strong temperature-dependent photovoltaic effects have been observed in the type of solar cell, which could be mainly attributed to CH_3NH_3PbI_3, showing a ferroelectric-paraelectric phase transition at low temperature(T < 160 K). An increase in temperature over the room temperature decreased the perovskite solar cell performance and reduced its efficiency from 16% to 9%. The investigation with electronic impedance spectroscopy reveals that at low temperature(T < 120 K) the charge transport layer limits the device performance, while at high temperature(T > 200 K), the interfacial charge recombination becomes the dominant factor.
