Proceedings of MATSUS23 & Sustainable Technology Forum València (STECH23) (MATSUS23)
DOI: https://doi.org/10.29363/nanoge.matsus.2023.173
Publication date: 22nd December 2022
Metal halide perovskites have now achieved impressive power conversion efficiencies (PCEs) in both single junction and tandem solar cells, making them promising candidates to solve energy and environment crisis. Record efficiencies of perovskite solar cells (PSCs) are obtained with doped spiro-OMeTAD as the hole transport layer (HTL). Conventionally, spiro-OMeTAD is doped by hygroscopic lithium salts with the assistance of volatile 4-tert-butylpyridine, which, however, brings a time-consuming doping process as well as poor device stability. To exclude the aforementioned disadvantages, researchers have tried to replace the LiTFSI with other dopants, like other metallic salts, F4TCNQ or organic radicals, which could also help to generate radicals improving the conductivity and get rid of the moisture sensitive byproduct LixOy. However, all the recipes with varied dopants can only achieve high PCE with tBP, but the mechanism behind have not been fully discussed to the point. Here, we develop an instantly effective (without post oxidation) doping strategy for spiro-OMeTAD, by employing stable organic radicals and ionic salts (referred to as ion-modulated (IM) radical doping). We achieve high power conversion efficiencies (PCEs) over 25% and much improved device stability under harsh conditions. In addition, the IM doping mechanism was revealed through advanced characterizations and theoretical analysis: electron transfer from neutral spiro-OMeTAD to radicals provide free holes to instantly increase the conductivity and work function (WF); the electrostatic interactions from ionic salts further modulate the WF by affecting the electron transfer activation energy. Our IM radical doping strategy proves effective with a variety of ionic salts, and the doped spiro-OMeTAD demonstrates universal applicability in different PSCs. The understandings on the doping mechanism also solve the mystery of tBP in conventional spiro-OMeTAD doping. Last but not least, the IM doping strategy addressed the importance of localized electrostatic environment in organic doping process, offering new insights for organic semiconductor doping by decoupling the conductivity and WF tunability, and can find applications in a number of optoelectronic devices.
We thank the supported by Swedish Research Council Vetenskapsrådet (grant 2018-04809), an ERC Starting Grant
(717026), the Knut and Alice Wallenberg Foundation (Dnr KAW 2019.0082), and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU 2009-00971). F.G. is a Wallenberg Academy Fellow.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.