Microcrystalline silicon thin film pin solar cells with a highly crystallized intrinsic μc‐Si:F:H absorber were prepared by RF‐plasma enhanced chemical vapour deposition using SiF4 as the gas precursor. The cells were produced with a vacuum break between the doped layer and intrinsic layer depositions, and the effect of different subsequent interface treatment processes was studied. The use of an intrinsic μc‐Si:H p/i buffer layer before the first air break increased the short circuit current density from 22.3 mA/cm2 to 24.7 mA/cm2. However, the use of a hydrogen‐plasma treatment after both air breaks without an interface buffer layer improved both the open circuit voltage and the fill factor. Although the material used for the absorber layer showed a very high crystalline fraction and thus an increased spectral response at long wavelengths, an open‐circuit voltage (VOC) of 0.523 V was nevertheless observed. Such a value of VOC is higher than is typically obtained in devices that employ a highly crystallized absorber as reported in the literature (see abstract figure). Using a hydrogen‐plasma treatment, a single junction μc‐Si:F:H pin solar cell with an efficiency of 8.3% was achieved.
We used amorphous silicon oxide (a‐Si1–xOx:H) and microcrystalline silicon oxide (µc‐Si1–xOx:H) as buffer layer and p‐type emitter layer, respectively, in n‐type silicon hetero‐junction (SHJ) solar cells. We proposed to insert a thin (2 nm) intrinsic amorphous silicon (a‐Si:H) thin film between the thin (2.5 nm) a‐Si1–xOx:H buffer layer and the p‐layer to form a stack buffer layer of a‐Si:H/a‐Si1–xOx:H. As a result, a high open‐circuit voltage (VOC) and a high fill factor (FF) were obtained at the same time. Finally, a high efficiency of 19.0% (JSC = 33.46 mA/cm2, VOC = 738 mV, FF = 77.0%) was achieved on a 100 μm thick polished wafer using the stack buffer layer.
Hydrogenated silicon (Si:H) film was grown by radio frequency plasma enhanced chemical vapor deposition (PECVD) method. The transition between hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon (μc-Si:H) was characterized by X-ray diffraction analysis. A semiconductor system was used to measure low frequency noise (1/f noise) and random telegraph switching noise of Si:H films. The results show that the 1/f noise of μc-Si:H is 4 orders of magnitude lower than that of a-Si:H and no RTS noise was found in both films. It also shows that using μc-Si:H instead of a-Si:H film as a sensing layer will enable the development of high performance uncooled microbolometer. 相似文献
Light trapping is a key issue in improving the efficiency of thin-film Si solar cells, and using a back reflector material plays a critical role in improving a cell's light-trapping efficiency. In this study, we developed n-type microcrystalline silicon oxide (n-μc-SiOx) films that are suitable for use as back reflectors in thin-film silicon solar cells. They exhibit a lower refractive index and lower absorption spectra, especially at long wavelengths of >700 nm, than conventional ZnO:Al materials, which are beneficial for this application. The n-μc-SiOx films were prepared by the PECVD (plasma-enhanced chemical vapor deposition) method and applied to the fabrication of back reflectors in μc-Si:H solar cells. We also characterized the changes in cell performance with respect to the refractive index, conductivity, and thickness of the n-μc-SiOx back reflectors. The novel back reflector boosts the total current density by up to 3.0% with the help of the enhanced long-wavelength response. It also improves open circuit voltage (Voc) and fill factor (FF), which may be attributed to the reduced shunt current caused by the anisotropic electrical characteristics of the n-μc-SiOx layer. Finally, we could achieve a conversion efficiency for the hydrogenated microcrystalline silicon (μc-Si:H) solar cells of up to 9.3% (Voc: 0.501 V, Jsc: 27.4 mA/cm2, FF: 0.68) using the n-μc-SiOx back reflector. 相似文献
Preparation of p-type hydrogenated microcrystalline silicon oxide thin films (p-μc-Si1−xOx:H) by 13.56 MHz RF-PECVD method for use as a p-layer of hetero-junction μc-Si:H solar cells is presented. We investigated effects of wide-gap p-μc-Si1−xOx:H layer on the performance of hetero-junction μc-Si:H solar cells under various light intensity. We observed that a wide-gap p-μc-Si1−xOx:H was effective in improving the open-circuit voltage (Voc) of the solar cells. We also confirmed that the Voc logarithmically increased with increasing light intensity, and the enhancement of Voc became larger with increasing band gap of p-layer. These results indicate that wide-gap p-μc-Si1−xOx:H is a promising material for use as window layer in hetero-junction μc-Si:H solar cells. 相似文献
Bulk heterojunction (BHJ) solar cells were fabricated based on blended films of a porphyrin derivative 5,10,15,20-Tetraphenyl-21H,23H-porphine zinc (ZnTPP) and a fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) as the active layer. The ZnTTP:PCBM BHJ solar cells were fabricated by spin-casting of the blended layer. The weight ratios of ZnTPP and PCBM were varied from 1:1 to 0:10. The electronic and optical properties of each cell were investigated. Optical density (OD) of the blended film for each cell was extracted from its reflection and transmission curves. OD and average absorption coefficients of the active materials were used to determine film thicknesses. Absorption spectra of each component material were compared with the spectra of the blended films. Current density–Voltage (J–V) characteristics were recorded under dark as well as under the illumination of AM 1.5G (1 sun) solar spectrum. The BHJ solar cell with ZnTPP:PCBM ratio of 1:9 showed the best performance . The values of RR, VOC , JSC , FF and η for these ratios were 106.3, 0.4 V, 1.316 mA/cm2, 0.4 and 0.21%, respectively. The cross-section of this device using SEM was also examined. 相似文献