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This paper describes a method for fabricating silicon heterojunction thin film solar cells with an ITO/p-type a-Si : H/n-type cSi structure by radiofrequency magnetron sputtering. A short-circuit current density and efficiency of 28.80 mA/cm² and 8.67% were achieved. Novel nanopatterned silicon wafers for use in cells are presented. Improved heterojunction cells are formed on a nanopatterned silicon substrate that is prepared with a self-assembled monolayer of SiO2 nanospheres with a diameter of 550 nm used as an etching mask. The efficiency of the nanopattern silicon substrate heterojunction cells was 31.49% greater than that of heterojunction cells on a flat silicon wafer. [ABSTRACT FROM AUTHOR]

In this study, the CuIn(Ga)Se2 (CIGS) crystalline quality and MoSe2 thickness of films produced by the rapid thermal selenization process under various selenization pressures were investigated. When the selenization pressure increased from 48 Pa to 1.45 x 104 Pa, the CIGS films were smooth and uniform with large crystals of varying sizes. However, the MoSe2 thicknesses increased from 50 nm to 2,109 nm, which created increased contact resistivity for the CIGS/MoSe2/Mo structures. The efficiency of CIGS solar cells could be increased from 1.43% to 4.62% due to improvement in the CIGS crystalline quality with increasing selenization pressure from 48 Pa to 1.02 x 10³ Pa. In addition, the CIGS crystalline quality and MoSe2 thickness were modified by the pressure released valve (PRV) selenization process method. The crystalline qualities of the CIGS films were similarly affected by the selenization pressure at 1.02 x 10³ Pa in the PRV selenization method and the MoSe2 thicknesses were reduced from 1,219 nm to 703 nm. A higher efficiency of 5.2% was achieved with the thinner MoSe2 obtained by using the PRV selenization method. [ABSTRACT FROM AUTHOR]

The absorption coefficient at 1.4 eV is divided by the value at 0.9 eV to obtain the factor used to judge the quality of µc-Si:H. PV device performance can be predicted by multiplying Voc with Isc when using this layer as an intrinsic layer. The results show a good relationship between the quality factor and the product of open-circuit voltage and short-circuit current. However, the final efficiency is influenced by the identities of the interface in the multilayer structure. [ABSTRACT FROM AUTHOR]

—The structural, optical and excitonic characteristics of urea doped CH 3 NH 3 PbI 3 (MAPbI 3) multi-crystalline thin films were investigated by using the X-ray diffraction patterns, atomic-force microscopic images, absorbance spectra, photoluminescence (PL) spectra and Raman scattering spectra. The surface-sensitive Raman scattering spectra show that the urea small molecules are mainly distributed in the top region of the MAPbI 3 thin films and thereby effectively passivating the electron-poor defects (interfacial MA cations) of MAPbI 3 thin films. Besides, the thermal annealing temperature and the concentration of urea additive both strongly influence the formation of MAPbI 3 thin films, which dominates the photovoltaic performance. The use of 5-wt% urea can increase the open-circuit voltage (V OC) and short-circuit current density (J SC) of the MAPbI 3 solar cells from 0.88 V to 19.75 mA/cm2 to 0.94 V and 22.97 mA/cm2, respectively. In addition, the reduced current hysteresis in the J-V curves of the MAPbI 3 solar cells can be explained as due to the effective defect passivation in the top region of the MAPbI 3 thin film by the oxygen-donors of the urea small molecules. Image 1 • The optoelectronic properties of urea-doped MAPbI 3 thin films are investigated. • The 5-wt% urea-doped MAPbI 3 thin film has the disk-like shaped grains. • The urea small molecules are mainly distributed in the top region of MAPbI3 thin films. • The V OC and J SC of MAPbI3 solar cells are simultaneously increased by using the urea additive. [ABSTRACT FROM AUTHOR]

CH 3 NH 3 PbI 3 (MAPbI 3) perovskite thin films were fabricated by using the one-step spin-coating method with a washing-enhanced nucleation (WEN) process under various dropping times, and the resultant thin films were characterized through the reflected-type optical microscope, atomic force microscope, transmittance spectrometer, X-ray diffractometer, photoluminescence spectrometer and water droplet contact-angle imaging system. The experimental results show that the dropping time for the WEN process strongly influences the surface morphology, surface wettability, crystallinity and refractive index of the resultant MAPbI 3 thin films, which dominates the contact at the hydrophilic MAPbI 3 /hydrophobic 6,6-phenyl C 61 butyric acid methyl ester (PCBM) interface and thereby determines the photovoltaic performance. In addition, this investigation helps further understand the effects of the WEN process on the formation of a closely-packed MAPbI 3 thin film. Image 1 • The dropping time for the WEN process highly influences the formation of perovskite films. • The dropping time largely changes the optical and structural properties of perovskite films. • The dropping time can change the surface wettability of perovskite films. • The dropping time dominates the photovoltaic performance of perovskite solar cells. [ABSTRACT FROM AUTHOR]