Cesium Lead Halide Perovskite Nanocrystals: Light ‎Absorbers in Solar cells
Fatima Haydous a, James Gardner a, Ute Cappel a
a KTH - Royal Institute of Technology Department of Chemistry Division of Applied Physical Chemistry Teknikringen 30 SE-114 28 Stockholm Sweden
nanoGe Perovskite Conferences
Proceedings of International Conference on Perovskite Thin Film Photovoltaics and Perovskite Photonics and Optoelectronics (NIPHO20)
Sevilla, Spain, 2020 February 23rd - 25th
Organizer: Hernán Míguez
Poster, Fatima Haydous, 107
Publication date: 25th November 2019

 

 

Today, nanoscale materials became embraced in the different areas of our daily lives from electronic and optoelectronic devices as smart phones and displays to medical applications as in biosensors and nanoscale assays. The large surface-to-bulk ratio in nanoscale materials grants them different chemical and physical properties than their corresponding bulk materials. Colloidal quantum dots (QDs) are semiconductor nanocrystals which have been extensively studied due to their unique properties including strong light absorption, large intrinsic dipole moments resulting in rapid charge separation and tunable bandgap that can be varied through particle size control. [1] In addition, since it was theoretically predicted that QDs can boost the power conversion efficiency in solar cells above the Shockley-Queisser limit due to multiple exciton generation, [2] they were employed as light absorbers in quantum dot solar cells. During the last decade, metal halide perovskites emerged as attractive solar cell materials mainly due to their impressive charge transport properties, strong light absorption, long carrier diffusion lengths, and tunable band gap through compositional modifications. [3], [4] Over a relatively short period of time, the power conversion efficiencies of the perovskite solar cells have increased rapidly from 3% to 25.2% as the last certified cell efficiency. This is mainly due to the improvements in perovskite component stoichiometry and optimizing the perovskite surface. However, the main issue with these solar cells is the stability due to their sensitivity to humidity and the solubility of the perovskite in water. To overcome this issue, colloidal QDs can be used which have better stability in water and also give the possibility of stabilizing new materials in the perovskite structure which are not stable in large crystals. [5] In this work, cesium lead halide QDs (CsPbX3, X = Br, I and mixed Br/I system) are synthesized in solution using the hot injection method. [6] The synthesized QDs were in the form of nanocubes exhibiting a strong emission under UV illumination. The QDs show a strong light absorption and photoluminescence that is tunable with the size of the quantum dots. The surface chemistry of the quantum dots is investigated by exchanging organic and inorganic surface ligands. Moreover, solar cells based on these perovskite QDs are fabricated and their performance is measured.

  


 

 

  

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