Controllable deposition of organic metal halide perovskite films with wafer-scale uniformity by single source flash evaporation

Abstract

Conventional solution-processing techniques such as the spin-coating method have been used successfully to reveal excellent properties of organic–inorganic halide perovskites (OHPs) for optoelectronic devices such as solar cell and light-emitting diode, but it is essential to explore other deposition techniques compatible with large-scale production. Single-source flash evaporation technique, in which a single source of materials of interest is rapidly heated to be deposited in a few seconds, is one of the candidate techniques for large-scale thin film deposition of OHPs. In this work, we investigated the reliability and controllability of the single-source flash evaporation technique for methylammonium lead iodide (MAPbI3) perovskite. In-depth statistical analysis was employed to demonstrate that the MAPbI3 films prepared via the flash evaporation have an ultrasmooth surface and uniform thickness throughout the 4-inch wafer scale. We also show that the thickness and grain size of the MAPbI3 film can be controlled by adjusting the amount of the source and number of deposition steps. Finally, the excellent large-area uniformity of the physical properties of the deposited thin films can be transferred to the uniformity in the device performance of MAPbI3 photodetectors prepared by flash evaporation which exhibited the responsivity of 0.2 A/W and detectivity of 3.82 × 1011 Jones.

Roadmap on commercialization of metal halide perovskite photovoltaics

“…To avoid the complication processes associated with maintaining the stoichiometry of multiple-cation mixed-halide perovskites during co-evaporation of a number of precursors, pre-synthesized PVK powders can be used as a single source for deposition. The techniques, such as flash evaporation and thermal ablation, allow a rapid increase in temperatures to evaporate the source material and condense the PVK on the substrates before decomposition [66]. Alternatively, the multi-component PVKs can also be obtained by selective substitution of the organic cations and/or halides during post-deposition treatments.…”

Optimized Substrate Orientations for Highly Uniform Metal Halide Perovskite Film Deposition

“…This is because the morphology of MHP crystals, including attributes such as grain size and film thickness, fundamentally dictates their carrier generation and transport properties, and hence, their overall optoelectronic performance. 16,20,22 While prior reports on vapor deposition of MHPs have emphasized their potential for large-area film growth, 23,24 the majority employ direct source evaporation onto a substrate in a vacuum chamber. 25,26 This approach inherently increases production cost due to the necessity of maintaining high-vacuum background and often suffers from a slow growth rate, 27 with growth variables closely tied to specific system geometries.…”

“…It is worth noting that the attainment of uniform film morphology is paramount for fabricating devices with consistent performance across a large area. This is because the morphology of MHP crystals, including attributes such as grain size and film thickness, fundamentally dictates their carrier generation and transport properties, and hence, their overall optoelectronic performance. ,, While prior reports on vapor deposition of MHPs have emphasized their potential for large-area film growth, , the majority employ direct source evaporation onto a substrate in a vacuum chamber. , This approach inherently increases production cost due to the necessity of maintaining high-vacuum background and often suffers from a slow growth rate, with growth variables closely tied to specific system geometries. In contrast, the tube furnace system offers versatility for the cost-effective growth of low-dimensional crystalline materials, such as 1D nanowires, , 2D materials, , and thin films. , With its capacity for high quality and yield, the tube furnace stands out as a more suitable option for potential scale-up processes, such as continuous roll-to-roll processing on a large-area substrate .…”

Ultrafast, Self-Powered, and Charge-Transport-Layer-Free Ultraviolet Photodetectors Based on Sequentially Vacuum-Evaporated Lead-Free Cs2AgBiBr6 Thin Films

“…Let alone, the spin-coating method falls far short of the industrial production required inherently. Vacuum evaporation has proved the superiority of high-quality and large-area perovskite films and has been applied to large-scale and high-performance photodetectors successfully. − In 2018, Liu et al constructed an evaporated Cs 2 AgBiBr 6 -based solar cell, obtaining a fair efficiency . However, high-performance photodetectors based on the evaporation-processed Cs 2 AgBiBr 6 thin film have not been exposed to public attention yet.…”