Intense Pulsed Light Processing of Perovskite Thin Films

Abstract

The manufacturing of solar photovoltaic panels has seen dramatic reductions in costs primarily through business innovations to the extent that the industry is quite large. The industry is dominated by a single technology, crystalline solar cells. The implementation of newer technologies that could further reduce costs are very attractive, especially technologies that can be adapted to continuous printing particularly involving polymer film substrate. The perovskite solar cells offers this; however, most of the processing techniques rely on extended thermal process or very exact solvent control. The Intense Pulsed Light (IPL) technology has been shown to rapidly process perovskite thin films and our recent work explores how the technology can open up the processing window. The Intense Pulsed Light technology is well suited to continuous manufacturing platforms such as roll-to-roll due to its very large processing area and rapid processing time scales. The IPL technique delivers high energy pulses of broad spectrum light (UV-Vis-NIR) in a very short duration (ms) over a large processing area (100 cm2). In the past few years, the method has found a number of applications within the flexible electronics industry as printed structures for wire traces, transparent conductors and RFID and is now gaining traction with more complex materials. The most promising opportunity for the IPL within photovoltaics is the application towards the flexible large area roll-to-roll production offered by the solution phase processed perovskites. In this paper we will discuss our work with the IPL and the extremely rapid processing of perovskite thin films using a number of precursor materials. We have shown the process for both the two-step and the single step deposition producing devices that perform as well as the traditional thermal processing at significantly faster speeds. This paper will also discuss the morphological changes that occur during the IPL with an intent to develop a robust process. Data from X-ray diffraction and scanning electron microscopy is used to describe the changes to the films, and current-voltage and electrochemical impedance spectroscopy is used to probe the devices.