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1. Spray-Cast Electrodes in Colloidal Quantum Dot Solar Cells for Portable Solar Energy Manufacturing

   https://doi.org/10.1109/PVSC40753.2019.8980617  

   Li, Lulin; Qiu, Botong; Lu, Chengchangfeng; Shimabukuro, Laura; Lin, Yida; Thon, Susanna M. (June 2019, Spray-Cast Electrodes in Colloidal Quantum Dot Solar Cells for Portable Solar Energy Manufacturing)

   Colloidal quantum dots are a promising candidate material for thin film solar cells due to their size-dependent band gap tunability and solution-based processing flexibility. Spray-casting technology has the potential to reduce the strict environmental requirements associated with traditional fabrication procedures for colloidal quantum dot solar cells, potentially enabling installation-site solar cell fabrication. Here, we demonstrate spray-casting of silver nanowire electrodes and zinc oxide electron transport layers, demonstrate their use in colloidal quantum dot solar cells, analyze the existing challenges in current spray-casting procedures, and outline a path to producing fully spray-cast colloidal quantum dot solar cells. 

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2. New Chalcogenide-Based Hole Transport Materials for Colloidal Quantum Dot Photovoltaics

   Rong, Eric; Bambini, Christianna; Lin, Yida; Lu, Chengchangfeng; Thon, Susanna M. (January 2021, Conference record of the IEEE Photovoltaic Specialists Conference)

   null (Ed.)

   Colloidal Quantum Dot (CQD) thin films are ad- vantageous for solar energy generation because of their low- cost and size-tunable, solution-processable nature. However, their efficiency in solar cells is limited in part by the performance of the hole transport layer (HTL). Through Solar Cell Capacitance Simulations and Transfer Matrix Method calculations, we show that significant photogeneration occurs in the standard HTL of ethanedithiol-passivated lead sulfide CQDs which is a problem due to the sub-optimal carrier mobility in this material. We report new HTLs composed of chalcogenide-based materials to address these issues, and demonstrate an absolute power conversion efficiency improvement of 1.35% in the best device. 

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3. Role of the ZnO electron transport layer in PbS colloidal quantum dot solar cell yield

   https://doi.org/10.1039/D3NR06558H  

   Chiu, Arlene; Lu, Chengchangfeng; Kachman, Dana E; Rong, Eric; Chintapalli, Sreyas M; Lin, Yida; Khurgin, Daniel; Thon, Susanna M (May 2024, Nanoscale)

   This review highlights recent advancements in the zinc oxide electron transport layer for PbS colloidal quantum dot solar cells. 

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4. Towards the commercialization of colloidal quantum dot solar cells: perspectives on device structures and manufacturing

   https://doi.org/10.1039/C9EE03348C  

   Lee, Hyunho; Song, Hyung-Jun; Shim, Moonsub; Lee, Changhee (February 2020, Energy & Environmental Science)

   Over the past decade, colloidal quantum dot solar cells (CQD-SCs) have been developed rapidly, with their performances reaching over 16% power conversion efficiency. Accompanied by the development in materials engineering (CQD surface chemistry) and device physics (structures and defect engineering), CQD-SCs are moving towards commercialization. A broad overview of the requirements for commercialization is thus timely and imperative. Broad comprehension of structure engineering, upscaling techniques, stability and the manufacturing cost of CQD-SCs is necessary and should be established. In this review, the development of device structures is presented with their corresponding charge transfer mechanisms. Then, we overview the upscaling methods for the mass production of CQD-SCs. Comparisons between each of the upscaling techniques suggest the most advanced process close to industrialization. In addition, we have investigated the origin of the photovoltaic (PV) performance degradation. The possible degradation sources are categorized according to external environmental factors. Moreover, strategies for improving the stability of CQD-SCs are presented. In the conclusion, we have reviewed the cost-effectiveness of CQD-SCs in terms of the niche PV market. Step-wise manufacturing cost analysis for the commercial CQD-SCs is presented. In the conclusion, the future direction for environment-friendly CQD-SCs is discussed. 

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5. Hybridization and deconfinement in colloidal quantum dot molecules

   https://doi.org/10.1063/5.0112443  

   Verbitsky, Lior; Jasrasaria, Dipti; Banin, Uri; Rabani, Eran (October 2022, The Journal of Chemical Physics)

   The structural, electronic, and optical properties of CdSe/CdS core–shell colloidal quantum dot molecules, a new class of coupled quantum dot dimers, are explored using atomistic approaches. Unlike the case of dimers grown by molecular beam epitaxy, simulated strain profile maps of free-standing colloidal dimers show negligible additional strain resulting from the attachment. The electronic properties of the relaxed dimers are described within a semiempirical pseudopotential model combined with the Bethe–Salpeter equation within the static screening approximation to account for electron–hole correlations. The interplay of strain, hybridization (tunneling splitting), quantum confinement, and electron–hole binding energies on the optical properties is analyzed and discussed. The effects of the dimensions of the neck connecting the two quantum dot building blocks, as well as the shell thickness, are studied. 

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