Solution-Processed SnO2 Quantum Dots for the Electron Transport Layer of Flexible and Printed Perovskite Solar Cells

Abstract

Flexible and printed perovskite solar cells (PSCs) fabricated on lightweight plastic substrates have many excellent potential applications in emerging new technologies including wearable and portable electronics, the internet of things, smart buildings, etc. To fabricate flexible and printed PSCs, all of the functional layers of devices should be processed at low temperatures. Tin oxide is one of the best metal oxide materials to employ as the electron transport layer (ETL) in PSCs. Herein, the synthesis and application of SnO2 quantum dots (QDs) to prepare the ETL of flexible and printed PSCs are demonstrated. SnO2 QDs are synthesized via a solvothermal method and processed to obtain aqueous and printable ETL ink solutions with different QD concentrations. PSCs are fabricated using a slot-die coating method on flexible plastic substrates. The solar cell performance and spectral response of the obtained devices are characterized using a solar simulator and an external quantum efficiency measurement system. The ETLs prepared using 2 wt% SnO2 QD inks are found to produce devices with a high average power conversion efficiency (PCE) along with a 10% PCE for a champion device. The results obtained in this work provide the research community with a method to prepare fully solution-processed SnO2 QD-based inks that are suitable for the deposition of SnO2 ETLs for flexible and printed PSCs.

Stepping toward Portable Optoelectronics with SnO2 Quantum Dot-Based Electron Transport Layers

“…The ETL inks are prepared using as-synthesized SnO 2 QDs and commercial SnO 2 NP colloidal dispersion solution. SnO 2 QDs are synthesized using a previously reported solvothermal technique and have an average size of ∼2.5 nm . The SnO 2 QD-based inks are obtained by dispersing SnO 2 QDs in an aqueous medium at a 2.0 wt % concentration .…”

“…SnO 2 is frequently used as an effective ETL material for PSCs due to its wide optical band gap (3.6–4.0 eV), deep conduction band, better transparency, high electron mobility (240 cm 2 V –1 s –1 ), long charge carrier diffusion length, and exceptional chemical stability. , However, processing of SnO 2 ETLs for PSCs may require temperatures above 180 °C. , Most reported printed and flexible PSCs employ commercially available SnO 2 NP dispersion solutions to prepare ETL inks and to fabricate ETLs of devices. However, the performance of resulting devices is still inferior to those fabricated on glass/TCO substrates and with SnO 2 ETLs processed at high temperatures. , Recently, ETL inks based on SnO 2 QD dispersion solutions have been used to manufacture efficient printed and flexible PSCs with SnO 2 ETLs deposited at lower temperatures . Hence, this report aims to investigate the performance and device properties of printed flexible PSCs with SnO 2 QD-based ETLs and compare them with similarly made devices employing commercially available SnO 2 NP-based ETLs.…”

Self-Powered Printed Flexible Bifacial Perovskite Photodetector

“…SnO 2 quantum dots ink was prepared in accordance with our previous studies. , Perovskite ink was prepared by dissolving 1 mol of MAI and PbI 2 in 700 μL of MA using a hot plate at 70 °C and a stirring speed of 460 rpm for 1 h. The final MAPbI 3 ink was obtained by addition of 700 μL of ACN and stirring at room temperature for 3 more hours. Lastly, Spiro-OMeTAD ink was prepared by dissolving 45 mg of Spiro-OMeTAD in 1 mL of CB.…”

Rapid scalable fabrication of roll-to-roll slot-die coated flexible perovskite solar cells using intense pulse light annealing

“…The deposition and thermal processing of SnO 2 in roll-to-roll manufacturing has been carried out where the thermal processing is accomplished in an oven, which improves the performance of the devices. 41,42 The IPL can be used to replace the oven, where the optimization of the IPL process involves multiple pulses as the web translates under the light source. The use of IPL with a SnO 2 thin lm for perovskites has previously been shown to maximize the binding energy of Sn 3d 5/2 , which leads to an improved charge transfer.…”