Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 53: Fundamentals of Perovskite Photovoltaics V (joint session CPP/DS/HL)

HL 53.6: Talk

Wednesday, March 22, 2017, 12:00–12:15, ZEU 250

Influence of the grain size on electronic properties of methylammonium lead iodide — •Oleksandra Shargaieva, Felix Lang, Jörg Rappich, Thomas Dittrich, Bernd Rech, and Norbert Nickel — Helmholtz-Zentrum Berlin, Institute for Silicon Photovoltaics, Kekulestr. 5, D-12489 Berlin (Germany)

Recently, hybrid perovskites have drawn the attention of researchers due to huge potential as absorbers in photovoltaic devices. The biggest advantage of such materials is the ease of the preparation within low costs leading to highly efficient solar cells. However, the solution based processing often lacks a control over crystal quality of obtained material. Despite the numerous reports showed different methods to improve morphology of perovskite layer, the influence of microscopic structure on properties of the material is not fully understood.

In this work we present a new approach to tune the grain size of CH3NH3PbI3 perovskite from 150 to 1000 nm with about 100 nm step. The new method is based on solid-phase recrystallization and provides a reliable way to control the grain size and hence, systematically study the influence of the grain size on optical and electrical properties of the material. The recrystallized perovskite layers were characterized using photoluminescence spectroscopy and surface photovoltage measurements. The recrystallized samples demonstrated a pronounce increase of the PL intensity due to lower defect density in treated material. Furthermore, our study showed a direct correlation between grain size and the transport length, L, with the maximum value of 900 nm.