Luminescent down-shifting CsPbBr₃ perovskite nanocrystals for flexible Cu(In,Ga)Se₂ solar cells

Abstract

To overcome the parasitic absorption of ultraviolet (UV) light in the transparent conductive oxide (TCO) layer of flexible Cu(In,Ga)Se 2 (CIGS) thin film solar cells, a CsPbBr 3 perovskite nanocrystal based luminescent down-shifting (LDS) layer was integrated on CIGS solar cells fabricated on a stainless steel foil. The CsPbBr 3 perovskite nanocrystal absorbs solar irradiation at wavelengths shorter than 520 nm and emits photons at a wavelength of 532 nm. These down-shifted photons pass the TCO layer without parasitic absorption and are absorbed in the CIGS absorber layer where they generate photocurrent. By minimizing the parasitic absorption in the TCO layer, the external quantum efficiency (EQE) of the CIGS solar cell with the CsPbBr 3 perovskite nanocrystal layer is highly improved in the UV wavelength range between 300 and 390 nm. Additionally, in the wavelength range between 500 and 1100 nm, the EQE is improved since the surface reflectance of the CIGS device with the CsPbBr 3 perovskite LDS layer was reduced. This is because the CsPbBr 3 perovskite nanocrystal layer, which has an effective refractive index of 1.82 at a wavelength of 800 nm, reduces the large refractive index mismatch between air (n air = 1.00) and the TCO layer (n ZnO = 1.96 at a wavelength of 800 nm). Both the short circuit current density and power conversion efficiency of the flexible CIGS solar cell integrated with the CsPbBr 3 perovskite are improved by 4.5% compared with the conventional CIGS solar cell without the CsPbBr 3 perovskite LDS layer. Fig. 5 J-V characteristics of the CIGS solar cells with and without the CsPbBr 3 perovskite. The inset table compares photovoltaic performance parameters of the two types of solar cells. Nanoscale PaperThis journal is

Down-Shifting and Anti-Reflection Effect of CsPbBr3 Quantum Dots/Multicrystalline Silicon Hybrid Structures for Enhanced Photovoltaic Properties

“…Compared with a relatively low PL QY (<50%) in Si QDs [31,32], IPQDs have PL QYs of 80%, 95%, 70%, for red, green, and blue emissions [33]. It has been reported that the spectral response with near UV light range of 300-390 nm of a Cu(In,Ga)Se 2 (CIGS) thin film solar cell was improved by taking advantage of the down-shifting effect of IPQDs [34]. In the present work, a colloidal approach is introduced to synthesize caesium lead bromide perovskite quantum dots (CsPbBr 3 QDs) that are cubic shaped with a mean size of 10 nm and whose room temperature PL peak is observed at 515 nm.…”

Electrochemical p-Doping of CsPbBr3 Perovskite Nanocrystals

“…Since the discovery of lead halide perovskite nanocrystals (NCs) in 2014, 1 these materials have been investigated as candidates for downconversion phosphors, 2 − 4 absorber layers in solar cells, 5 − 7 and emitting layers in light-emitting diodes (LEDs). 8 − 14 Important advantages of perovskite NCs are their facile synthesis 15 − 18 and their intrinsic defect tolerance.…”

Improving Ultraviolet Responses in Cu2ZnSn(S,Se)4 Thin-Film Solar Cells Using Quantum Dot-Based Luminescent Down-Shifting Layer

“…Furthermore, solar cells made of Cu 2 ZnSn(S,Se) 4 (CZTSSe) or Cu(In,Ga)(S,Se) 2 (CIGS) mainly use CdS as the buffer layer, which has the disadvantage of absorbing ultraviolet (UV) light [ 1 , 2 , 3 ]. To solve this narrow absorption band problem, researchers are studying luminescent down-shifting (LDS) layers that can widen the absorption bands via simpler methods than multijunction or tandem solar cells [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. The quantum dot (QD)-based LDS layer utilizes the properties of QDs that absorb light of short wavelengths and emit light with large wavelengths.…”

“…Therefore, more photons in the semiconductors lead to the generation of more electron-hole pairs, and the photovoltaic current increases. LDS layers have been applied to CdTe [ 7 ], silicon [ 9 , 10 , 11 ], and CIGS [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ] solar cells, but no results have been reported yet for CZTSSe solar cells. Lesyuk et al calculated the effects of QD-based LDS layers on Cu 2 ZnSnS 4 (CZTS) solar cells using the Monte Carlo ray-tracing method, but no experiments were described [ 5 ].…”