Thermal stability of mobility in methylammonium lead iodide

Abstract

Metal halide perovskites (MHPs) are a fascinating class of photovoltaic materials; possessing distinctive optoelectronic properties and simple processing routes. The most significant remaining barrier to commercialization is their poor stability under ambient conditions. While the stability of electronic parameters in this class of material has been studied extensively, to date the overwhelming majority of such studies have been carried out using PV devices. The presence of electrodes and transport layers in this approach involves both implicit encapsulation, and modification of interface properties. To develop an extensive understanding of environmental stability of electronic properties in MHPs, it is crucial to study the electronic properties of the material in isolation, rather than in a finished device. In this work, we have studied the thermal stability of electronic properties of solution processed methylammonium lead iodide (MAPbI 3 ). MAPbI 3 thin films were subjected to extended periods of elevated temperatures before their electronic properties were probed using time-resolved microwave conductivity (TRMC), a contactless technique enabling extraction of a proxy for the material's mobility, without the need to form a device. The films were analysed with x-ray absorption spectroscopy (XAS) to study the impact of temperature on film microstructure. We observed an increase in average Pb-I bond length with increased annealing temperature.

Long-range exciton diffusion in molecular non-fullerene acceptors

“…TRMC measurements were performed using a system described in a previous report 62 . The measurements were carried out on bilayer CuSCN/NFA films, which were deposited on 0.9 cm × 0.9 cm quartz substrates.…”

Excellent Intrinsic Long‐Term Thermal Stability of Co‐Evaporated MAPbI3 Solar Cells at 85 °C

“…The solution-processed methylammonium lead iodide (MAPbI 3 ) film is unstable under high-temperature stress even in an inert environment. [25][26][27] On the other hand, MAPbI 3 PSCs can achieve good thermal stability only when they incorporating large or inorganic cation, [28,29] additive, [30][31][32][33] or carbon electrode. [34] Similar strategies have also been used to achieve stable operation under continuous illumination in MAPbI 3 PSCs.…”

Inter‐Sample and Intra‐Sample Variability in Electronic Properties of Methylammonium Lead Iodide

“…The TRMC measurements were carried out as described in a previous work. [25,53] All measurements were conducted in air, without encapsulation, in the over-coupled regime. Spatial mapping was conducted in an analogous manner but where a pinhole was placed between the incident laser beam and the sample.…”