Recent development and understanding of polymer–nanocrystal hybrid solar cells

Chen, Zhaolai; Du, Xiaohang; Zeng, Qingsen; Yang, Bai

doi:10.1039/c7qm00022g

Cited by 23 publications

(23 citation statements)

References 94 publications

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“…Solution-processed nanocrystal (NC) solar cells have demonstrated as a candidate for low cost, environmentally friendly, and large scale “roll to roll” printing product due to their low raw material consumption and simple fabrication process [ 1 , 2 , 3 ]. Recently, intensive investigations have been focused on CdTe NC solar cells with an inverted structure [ 4 , 5 ]. Comparing to the conventional CdTe NC solar cells using indium tin oxide (ITO) as the anode, devices with an inverted structure have many advantages, such as long-term stability under ambient conditions by avoiding the usage of low work-function metal cathode on the top of the device and better photon absorption efficiency due to the small distance between the active layer and the illumination source [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Hole Transfer Layer Engineering for CdTe Nanocrystal Photovoltaics with Improved Efficiency

Jiang

Pan

et al. 2020

Nanomaterials

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Interface engineering has led to significant progress in solution-processed CdTe nanocrystal (NC) solar cells in recent years. High performance solar cells can be fabricated by introducing a hole transfer layer (HTL) between CdTe and a back contact electrode to reduce carrier recombination by forming interfacial dipole effect at the interface. Here, we report the usage of a commercial product 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro) as a hole transfer layer to facilitate the hole collecting for CdTe nanocrystal solar cells. It is found that heat treatment on the hole transfer layer has significant influence on the NC solar cells performance. The Jsc, Voc, and power conversion efficiency (PCE) of NC solar cells are simultaneously increased due to the decreased contact resistance and enhanced built-in electric field. We demonstrate solar cells that achieve a high PCE of 8.34% for solution-processed CdTe NC solar cells with an inverted structure by further optimizing the HTL annealing temperature, which is among the highest value in CdTe NC solar cells with the inverted structure.

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Section: Introductionmentioning

confidence: 99%

Hole Transfer Layer Engineering for CdTe Nanocrystal Photovoltaics with Improved Efficiency

Jiang

Pan

et al. 2020

Nanomaterials

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confidence: 99%

Mediating Colloidal Quantum Dot/Organic Semiconductor Interfaces for Efficient Hybrid Solar Cells

Kim

Baek

Kim

et al. 2021

Advanced Energy Materials

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of two different materials. [7,[16][17][18][19] It also enables the hybrids to inherit the superior mechanical flexibility of organic materials. [20,21] Since the first CQD/ organic hybrid solar cells were proposed, [22] efforts have been underway to improve the PCE. Although many previous studies successfully demonstrated complementary absorption, the PCEs of hybrid solar cells are still affected by inefficient charge extraction, caused by 1) the short exciton diffusion length in polymers, [19] 2) poor nanomorphology of the CQD:polymer mix causing unfavorable charge transfer pathways, and 3) local trap sites at the interfaces of CQD and polymer. [18] Various strategies such as exploration of new materials for use in the hybrids, [23][24][25][26][27] tuning CQD size, [18,28] molecular modification, [18,29] and ligand exchange [30,31] have been proposed to enhance the charge extraction in CQD/polymer hybrids. Among them, tuning the CQD surface using organic/inorganic ligands has been widely investigated because it can modify the CQD surface that affects the electrical properties. [16,32,33] Recently, a small-molecule bridge was employed in CQD/ organic hybrid solar cells to overcome the short exciton diffusion length problem; [34,35] however, the hybrid cells still suffer from substantial trap sites at the CQD/organic interfaces, limiting charge extraction. The CQD/organic interfaces have many trap sites due to the large difference in surface energy between the CQD and polymer, [18] the presence of insulating ligands, [16] and defects on the CQD surfaces. [36] These CQD/polymer interfaces potentially hinder charge transport and induce bimolecular recombination.In this work, we systematically investigated how the CQD/ organic interfaces influenced the charge transport properties. First, we replaced the native ligand of CQD with halides to form conventional CQD solids. [37] Subsequently, a polymer layer was stacked onto the CQD solid to form a CQD/organic heterointerface. Additionally, an auxiliary interfacial layer passivated by various organic ligands was implemented at the CQD/polymer interface. The interfacial layer that provides the cascading conduction band offset (ΔE C ) between CQD and polymer relieved band bending that adversely hinders the charge transfer at CQD/polymer interfaces. The reduced band bending facilitated the charge transfer across the heterojunction by suppressing charge accumulation -as confirmed by transient photocurrent (TPC) spectroscopy -and by reducing bimolecular recombination at the CQD/polymer interfaces.Emerging semiconducting materials including colloidal quantum dots (CQDs) and organic molecules have unique photovoltaic properties, and their hybridization can result in synergistic effects for high performance. For realizing the full potential of CQD/organic hybrid devices, controlling interfacial properties between the CQD and organic matter is crucial. Here, the electronic band between the CQD and the polymer layers is carefully modulated by inserting an interfacial layer treated...

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“…The intimate contact between the active layer and hole/electron blocking layers is essential for blocking injected charges and effectively collecting carriers to the electrodes (Chen et al, 2017 ; Cheng et al, 2019 ). However, these additional layered transporting and blocking layers deposited by spin-coating or thermal evaporation have a low mobility lifetime and high trap density because these layers are amorphous and have lattice mismatch on PSC interfaces (Lin et al, 2015 ; Zhang et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Enhanced Performance of Perovskite Single-Crystal Photodiodes by Epitaxial Hole Blocking Layer

Pan

Wang

et al. 2020

Front. Chem.

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Introducing hole/electron transporting and blocking layers is considered to enhance the performance of electronic devices based on organic–inorganic hybrid halide perovskite single crystals (PSCs). In many photodiodes, the hole/electron transporting or blocking materials are spin-coated or thermal-evaporated on PSC to fabricate heterojunctions. However, the heterojunction interfaces due to lattice mismatch between hole/electron, transporting or blocking materials and perovskites easily form traps and cracks, which cause noise and leakage current. Besides, these low-mobility transporting layers increase the difficulty of transporting carriers generated by photons to the electrode; hence, they also increase the response time for photo detection. In the present study, MAPbCl 3 -MAPbBr 2.5 Cl 0.5 heterojunction interfaces were realized by liquid-phase epitaxy, in which MAPbBr 2.5 Cl 0.5 PSC acts as an active layer and MAPbCl 3 PSC acts as a hole blocking layer (HBL). Our PIN photodiodes with epitaxial MAPbCl 3 PSC as HBL show better performance in dark current, light responsivity, stability, and response time than the photodiodes with spin-coated organic PCBM as HBL. These results suggest that the heterojunction interface formed between two bulk PSCs with different halide compositions by epitaxy growth is very useful for effectively blocking the injected charges under high external electric field, which could improve the collection of photo-generated carriers and hereby enhance the detection performance of the photodiode. Furthermore, the PIN photodiodes made of PSC with epitaxial HBL show the sensitivities of 7.08 mC Gy air −1 cm −2 , 4.04 mC Gy air −1 cm −2 , and 2.38 mC Gy air −1 cm −2 for 40-keV, 60-keV, and 80-keV X-ray, respectively.

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Recent development and understanding of polymer–nanocrystal hybrid solar cells

Cited by 23 publications

References 94 publications

Hole Transfer Layer Engineering for CdTe Nanocrystal Photovoltaics with Improved Efficiency

Hole Transfer Layer Engineering for CdTe Nanocrystal Photovoltaics with Improved Efficiency

Mediating Colloidal Quantum Dot/Organic Semiconductor Interfaces for Efficient Hybrid Solar Cells

Enhanced Performance of Perovskite Single-Crystal Photodiodes by Epitaxial Hole Blocking Layer

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