Effects of Photonic Curing Processing Conditions on MAPbI₃ Film Properties and Solar Cell Performance

Abstract

Thermal annealing is the most used postdeposition materials processing method in laboratory research, but due to its slow speed and high energy cost, it is not compatible with the upscaling and commercialization of perovskite solar cell (PSC) manufacturing. Here, we adapt photonic curing (PC), which uses millisecond light pulses to deliver energy to the sample, to replace thermal annealing for crystallization of methylammonium lead iodide (MAPbI 3 ) films and rapid fabrication of PSCs. We study how PC conditions affect the outcome of MAPbI 3 conversion from the precursor to the crystalline perovskite phase by evaluating the films' optical, crystalline, and morphological properties, as well as PSC performance. The results are understood using simulated film temperature profiles. We show that MAPbI 3 is readily converted under a wide range of PC conditions. While previous reports all used short pulses (<3 ms), we find that longer pulses produce more dense films and higher-performing PSCs. We achieve a champion power conversion efficiency in a PCprocessed MAPbI 3 PSC of 11.26% under forward scan and 10.34% under reverse scan, with the processing time for the MAPbI 3 layer reduced by 30,000-fold, from 10 min to 20 ms. Using a 6 in. lamp, spatial uniformity tests show a cross-web efficiency variation of 5%. Our results indicate that using longer pulse lengths, >10 ms, is the best PC strategy for perovskite conversion, and PC is a promising annealing method for large-area, high-throughput PSC manufacturing.

Photonic Curing of Nickel Oxide Transport Layer and Perovskite Active Layer for Flexible Perovskite Solar Cells: A Path Towards High-Throughput Manufacturing

“…For large-area manufacturing, two issues are of particular concern: uniformity and web speed. Xu et al (2020) have already demonstrated ∼5% variation across 5 inches in the cross-web direction for PC MAPbI 3 films. Down-web uniformity using photonic curing for processing is a concern because the light pulses are discrete while the substrate is conveyed at high speed underneath the lamp.…”

“…Photonic -30 pulses) to the sample at repetition rates ranging from 0.1 to 1 Hz and a lamp voltage of 500 or 700 V. All PC MAPbI 3 samples were processed using a single pulse with a lamp voltage of 300 V and a pulse length of 20 ms. This PC processing condition for MAPbI 3 was adapted from our previous work on 1 mm glass (Xu et al, 2020), with the lamp voltage reduced for the thinner WG substrates. To compare the PC MAPbI 3 conversion on top of TA or PC NiO x HTL, we first conducted XRD to confirm the crystallinity.…”

“…Supplementary Figure S6 shows how T p changes with pulse length at 500 V lamp voltage. For our sample in our tool at the maximum 500 V lamp voltage, t 0 equals ∼3 ms. T p increases with pulse length for pulses <3 ms until it reaches the single-pulse saturation value at ∼ 3 ms. T p is then equal to the single-pulse saturation value, independent of pulse length, for pulses >3 ms. t 0 and the associated single-pulse saturation T p value depend on the photonic curing tool and parameters used particularly lamp voltage and number of lamp drivers as well as the sample properties and boundary conditions (Xu et al, 2020). Higher lamp voltages will produce higher T p values for a given pulse length because more power is being delivered to the sample.…”

“…It has also been demonstrated for fabricating ZrO 2 (Daunis et al, 2020) and HfO 2 (Tetzner et al, 2014) dielectric films from sol-gel precursors on flexible and rigid substrates, respectively. For PSCs, a few research groups have demonstrated that photonic curing can convert perovskite active layers (Lavery et al, 2016;Troughton et al, 2016;Muydinov et al, 2018;Xu et al, 2020). Separately, photonic curing has also been reported for making mesoporous or compact TiO 2 (Das et al, 2016;Feleki et al, 2017;Luo et al, 2017) or SnO 2 (Zhu et al, 2017) ETLs with thermally annealed perovskite active layers.…”

Annealing Engineering in the Growth of Perovskite Grains

“…The intense pulsed light is a non-contact rapid heating method which can offer fast millisecond pulses of broad spectrum light (190-1100 nm) from xenon lamps [74]. Xenon lamps are used to provide high-energy pulse light to 150 J/cm 2 for perovskite annealing, and can achieve thin film crystallization at the millisecond scale [54,70,[75][76][77][78][79]. Druffel et al successfully employed intense pulsed light generated by a xenon lamp to sintering of MAPbI 3 on a mesoporous TiO 2 substrate for first time [76].…”