High-Efficiency and Stable Perovskite Solar cells with Negligible Hysteresis via Interface Engineering

Interfacial carrier recombination directly impacts perovskite photovoltaic performance, leading to reduced carrier lifetimes, and voltage loss. The interaction of interfacial defect and mobile ions is also thought to be responsible for the current-voltage hysteresis which is observed in many perovskite cells. Consequently, rational surface contact passivation techniques are critical for further improving the performance of the perovskite solar cells. Here we introduce a simple, one-step, solution-based method for fabricating high quality indium-doped titanium oxide electron transport layers. We show via systematic materials characterization that indium-doping improves both the conductivity of the transport layer and the band alignment at the ETL/perovskite interface compared to pure TiO2. This leads to an increased fill-factor and voltage of perovskite cells. And then, we demonstrate a thin passivation layer consisting of PMMA/PCBM mixture which can effectively passivate the defects/trap states at or near to the perovskite/TiO2 interfaces, and thus significantly suppress the interfacial recombination. The passivation layer results in a considerable reduction in hysteresis and a simultaneous increase in Voc from 1.1 V (highest Voc for the control cell) to ~1.18 V for mixed cation 1.55eV bandgap perovskite solar cells. As a result, we successfully obtained efficient and stable perovskite solar cells with a steady-state PCE of 20.4% and negligible hysteresis over a large range of scan rates.
 
 
 

Biography

Mr Jun Peng is a Ph.D. student in RSE. His research has been focusing on high-efficiency perovskite solar cell and perovskite/silicon tandem solar cells. The relevant papers of this seminar have been published in Advanced Energy Materials and Energy & Environmental Science.
 
 
 

Date & time

4.10–5pm 29 Jun 2017

Location

Room:Seminar Room

Internal speakers

Mr Jun Peng

Contacts

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