Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
DOI: https://doi.org/10.29363/nanoge.hopv.2022.154
Publication date: 20th April 2022
While the band diagram is well understood for most photovoltaic technologies, the distribution and magnitude of the built-in voltage (VBI) in the field of perovskite solar cells remains poorly understood. The VBI can be understood as an internal driving force for charges and is defined as the total voltage drop across all layers of the device. As such, the VBI strongly influences the charge transport and recombination processes in the absorber layer and at the interfaces and with that the open-circuit voltage (VOC) and fill factor (FF) of the device. Moreover, it is expected that a comparatively large VBI (similar to the VOC) is required to achieve well performing devices in the presence of significant interface recombination.
In this work, we have systematically studied the VBI in pin-type perovskite solar cells based on different hole transport layers (HTLs). To this end, we determined the surface photovoltage (SPV) of partial and complete device stacks layer-by-layer by measuring the work function (WF) under dark and light conditions with Kelvin probe and photoemission spectroscopy measurements in 3 different laboratories and compared the SPV to the VOC of full devices. Our results demonstrate that the SPV increases upon the addition of each additional layer until the SPV equals the VOC of the full device. This is consistent with the assumption that both electron and hole transport layers (HTL/ETL) increase the VBI of the device, however, the contribution of both the hole and electron transport layer (HTL/ETL) to the total SPV of the device is not really significant (only in the range of ≈100 – 200 meV). In contrast, in all cases, the largest contribution to the SPV originates from the addition of the top metal electrode (≈700 meV), upon completion of the device. The results suggest that the VBI of pin-type perovskite solar cells is largely a result of effectively work-function mismatched electrodes. Moreover, with regard to films (or incomplete cell stacks), our simulations show that a large quasi-Fermi level splitting (>VOC) can be achieved without a significant internal field, which is consistent with the experimental data. Overall, this work presents a closer and more accurate look into the band diagram of pin-type perovskite solar cells and enables a better understanding of how the internal field impacts the non-radiative recombination losses and the overall performance of perovskite solar cells.
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.