Improved planar perovskite solar cells using the modified hole transporting layer and solvent annealing

Organometal trihalide perovskites have been demonstrated as excellent light absorbers for high efficiency solar cell [1]. In this work, Glass/ITO/PEDOT:PSS/Perovskite/PCBM/Ag planar heterojunction structure was designed and investigated. For the reference cell, the efficiency of 12.5 % was achieved. An relative low J(sc) was exhibited at the result, mainly owing to the low conductivity of the electric transport layer - PEDOT:PSS. By controlling the amount of DMSO doped in PEDOT:PSS, a superior device was obtained with the efficiency of 13.6% although the roughness of the PEDOT: PSS layer was also increasing with doping DMSO. Furthermore, another key factor for a perovskite solar cell is the high crystallization of the perovskite layer[2]. Solvent annealing was adopted to improve the crystallization in this work. With dropping IPA around the solar cell and annealing for 20 minute, a surprising characteristics of the device with the efficiency of 15%, V-OC of 0.99 V, Fill Factor of 67.9%, J(SC) of 22.3mA/cm(2) was obtained.