The poor stability of CsPbX₃ quantum dots (QDs-CsPbX₃) under wet conditions is still considered to be a key issue. In order to overcome this problem, this study presents a high molecular weight polymer matrix (polymethylmethacrylate, PMMA) incorporated into the QDs-CsPbBr₃ to improve its stability and maintain its excellent optical properties. In this study, the Cs₂CO₃, PbO, Tetrabutylammonium Bromide (TOAB) powder, oleic acid, and toluene solvent were uniformly mixed and purified to prepare high-quality QDs powders. Then, hexane was used as a dispersing agent for the QD powder to complete the perovskite QDs-CsPbBr₃ solution. Finally, a solution with different proportions of quantum dots CsPbBr₃ and PMMA was prepared and discussed. In the preparation of thin films, firstly, a thin film with the structure of glass/QD-CsPbBr₃/PMMA was fabricated in a glove box using a well-developed QDs-CsPbBr₃ solution by changing the ratio of CsPbBr₃:PMMA. The material analysis of QDs-CsPbBr₃ thin films was performed with photoluminescence (PL), transmittance, absorbance, and transmission electron microscopy (TEM). The structures and morphologies were further examined to study the effect of doped PMMA on perovskite QDs-CsPbBr₃.

We describe a method to enhance power conversion efficiency (PCE) of MAPbI₃ perovskite solar cell by inserting a FAPbX₃ perovskite quantum dots (QD-FAPbX₃) layer. The MAPbI₃ and QD-FAPbX₃ layers were prepared using a simple, rapid spin-coating method in a nitrogen-filled glove box. The solar cell structure consists of ITO/PEDOT:PSS/MAPbI₃/QD-FAPbX₃/C₆₀/Ag, where PEDOT:PSS, MAPbI₃, QD-FAPbX₃, and C₆₀ were used as the hole transport layer, light-absorbing layer, absorption enhance layer, and electron transport layer, respectively. The MAPbI₃/QD-FAPbX₃ solar cells exhibit a PCE of 7.59%, an open circuit voltage (Voc) of 0.9 V, a short-circuit current density (Jsc) of 17.4 mA/cm², and a fill factor (FF) of 48.6%, respectively.

We demonstrate a method to enhance the power conversion efficiency (PCE) of MAPbI₃ perovskite solar cells through localized surface plasmon (LSP) coupling with gold nanoparticles:CsPbBr₃ hybrid perovskite quantum dots (AuNPs:QD-CsPbBr₃). The plasmonic AuNPs:QD-CsPbBr₃ possess the features of high light-harvesting capacity and fast charge transfer through the LSP resonance effect, thus improving the short-circuit current density and the fill factor. Compared to the original device without Au NPs, a 27.8% enhancement in PCE of plasmonic AuNPs:QD-CsPbBr₃/MAPbI₃ perovskite solar cells was achieved upon 120 μL Au NP solution doping. This improvement can be attributed to the formation of surface plasmon resonance and light scattering effects in Au NPs embedded in QD-CsPbBr₃, resulting in improved light absorption due to plasmonic nanoparticles.

High-quality perovskite CsPbBr₃ quantum dots (QDs-CsPbBr₃) were prepared using the ultrasonic oscillation method, which is simple and provides variable yield according to requirements. The emission spectra over a large portion of the visible spectral region (450–650 nm) of QD-CsPbX₃ (X = Cl, Br, and I) have tunable compositions that can be halide exchanged using the halide anion exchange technique and quantum size-effects. A strong peak with high intensity of (200) lattice plane of purified QDs-CsPbBr₃ film is obtained, confirming the formation of an orthorhombic perovskite crystal structure of the Pnma space group. The photoluminescence of QDs-CsPbBr₃ was characterized using a narrow line-width emission of 20 nm, with high quantum yields of up to 99.2%, and radioactive lifetime increasing to 26 ns. Finally, through the excellent advantages of QDs-CsPbBr₃ mentioned above, purified perovskite QDs-CsPbBr₃ as an active layer was utilized in perovskite quantum dot light-emitting diodes structure applications. As a result, the perovskite QDs-CsPbBr₃ light-emitting diodes (LEDs) exhibits a turn-on voltage of 7 V and a maximum luminance of 5.1 cd/m².

In this paper, a thermally crosslinkable 9,9-Bis[4-[(4-ethenylphenyl)methoxy]phenyl]-N2,N7-di-1-naphthalenyl-N2,N7-diphenyl-9H-fluorene-2,7-diamine (VB-FNPD) film served as the hole transporting layer (HTL) of perovskite CsPbBr₃ quantum-dot light-emitting diodes (QD-LEDs) was investigated and reported. The VB-FNPD film crosslinked at various temperatures in the range of 100~230 °C followed by a spin-coating process to improve their chemical bonds in an attempt to resist the erosion from the organic solvent in the remaining fabrication process. It is shown that the device with VB-FNPD HTL crosslinking at 170 °C has the highest luminance of 7702 cd/m², the maximum current density (J) of 41.98 mA/cm², the maximum current efficiency (CE) of 5.45 Cd/A, and the maximum external quantum efficiency (EQE) of 1.64%. Our results confirm that the proposed thermally crosslinkable VB-FNPD is a candidate for the HTL of QD-LEDs.

Perovskite solar cells (PeSCs) were fabricated by using Cs _x FA_1-x PbI_3-x Cl _x as the photoactive layer, and the effects of different proportions of cesium chloride (CsCl)/formamidinium iodide on perovskites were investigated. Cesium (Cs) can stabilize the α phase of the perovskite, while chlorine (Cl) can increase the size and crystallinity of perovskite crystals and reduce non-radiative cladding, thereby improving the performance of the overall device. The maximum power conversion efficiency (PCE) measured for Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSCs was 18.9%. To further improve the photovoltaic characteristics of PeSCs, Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSCs were introduced into different concentrations of phenethylammonium iodide (PEAI) to modify the interface between the NiO _x hole transport layer (HTL) and the perovskite photoactive layer, which can simultaneously promote excellent crystallinity of the perovskite layer and passivated interfacial defects, reducing recombination near the perovskite/HTL interface in PeSCs, thereby increasing the efficiency of the device. Compared with the control Cs_0.2FA_0.8PbI_2.8Cl_0.2-based PeSC, the PCE of PeSC with the PEAI (10 mg/mL)-modified NiO _x /perovskite interface increased significantly from 18.9 to 20.2%.