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Windows integrated with PV can provide electrical energy and control the energy flow (heat and light) through the windows. With the objective of evaluate the potential application of window integrated PV in southwest China, the performance of silicon PV windows was comprehensively studied. A test unit was developed to monitor the performance of window integrated PV, then a validated comprehensive approach integrated with heat transfer, optical, electrical and building simulation model was used to comprehensively evaluate the performance of the window integrated PV under various climatic conditions in southwest China. The effects of the air gap on window thermal performance, window orientation, different window-to-wall ratio and coverage ratio of PV cells are evaluated. It was found that a maximum energy saving could be achieved, when the PV window is installed on the south facing facade with a PV cell coverage ratio of 0,87, air gap of 9 mm between the two glazing panes. It was found that a maximum energy saving of 983 kWh was achieved in Lhasa. A highest energy saving ratio of 83% was found in Kunming. The window integrated PV shows good energy saving potential under different climatic conditions in Southwest China.

In this work, boron paste was coated on the silicon surface by spin-coating method, and the boron-doped emitter and phosphorus-doped back surface field were fabricated in one co-diffusion process, because the boron paste acted as a barrier during phosphorus diffusion. Then, n-PERT (Passivated Emitter Rear Totally-diffused cell) solar cells were successfully prepared by this B/P co-diffusion method with the front efficiency of 20.41% and the back efficiency reaching 18.32%. It was demonstrated that the emitter and back surface field formed a good passivation layer on top by thermal oxidation respectively, which enabled open-circuit voltage to reach 648.7 mV. It should be emphasized that the whole process was effectively simplified compared with the conventional process of n-PERT solar cells. Thus, these first results indicate that B/P co-diffusion might be a promising alternative method for mass production of the n-PERT solar cells. g

In the photovoltaic industry, an antireflection coating consisting of three SiNx layers with different refractive indexes is generally adopted to reduce the reflectance and raise the efficiency of monocrystalline silicon PERC (passivated emitter and rear cell) solar cells. However, for SiNx, a refractive index as low as about 1.40 cannot be achieved, which is the optimal value for the third layer of a triple-layer antireflection coating. Therefore, in this report the third layer is replaced by SiOx, which possesses a more appropriate refractive index of 1.46, it and can be easily integrated into the SiNx deposition process with the plasma-enhanced chemical vapor deposition (PECVD) method. Through simulation and analysis with SunSolve, three different thicknesses were selected to construct the SiOx third layer. The replacement of 15 nm SiNx with 30 nm SiOx as the third layer of antireflection coating can bring about an efficiency gain of 0.15%, which originates from the reflectance reduction and spectral response enhancement below about 550 nm wavelength. However, because the EVA encapsulation material of the solar module absorbs light in short wavelengths, the spectral response advantage of solar cells with 30 nm SiOx is partially covered up, resulting in a slightly lower cell-to-module (CTM) ratio and an output power gain of only 0.9 W for solar module.

Thermal comfort is an important aspect to take into consideration for the indoor environment of a building integrated with a semi-transparent Photovoltaics (STPV) system. The thermal comfort of units with photovoltaic windows and that of conventional windows, which is an ordinary without PV, were evaluated via on-site tests and questionnaires. Using the thermal comfort investigation of the test rig, the maximum difference in air temperature was found to be around 5 &deg, C between test unit and comparison unit. The predicted mean vote (PMV)&ndash, predicted percentage dissatisfied (PPD) value of the test unit was better than that of the comparison unit. It was observed that on sunny days, the PMV value ranged from 0.2 (nature) to 1.3 (slightly warm) in the test unit, and that of the comparison unit was 0.7 (slightly warm) to 2.0 (warm), thereby providing better thermal comfort, especially during mornings. The maximum difference in PPD values was found to reach 27% between the two units at noon. On cloudy days, the difference was negligible, and the thermal sensation between the foot and the head were almost the same. Fifty respondents were asked to complete a carefully designed questionnaire. The thermal sensation of the test unit was better than that of comparison unit, which corresponded with the test results. Thermal, lighting, acoustic, and other environment comfort scores were combined, and the acceptance of the test unit with the STPV windows was found to be 73.8%. The thermal sensation difference between men and women was around 5%. Thus, during summer, STPV windows can improve the thermal comfort and potentially reduce the air-conditioning load.

PERC solar cell passivated on the backside with AlOx and SiNx was introduced to construct the perovskite/silicon four-terminal tandem solar cell, because of its outstanding spectral response at the long wavelength region and much lower cost than SHJ and IBC. Different from the vast majority of the related reports, which were focused on the improvement of perovskite top cell, the silicon bottom cell was optimized here to promote the tandem efficiency. The central wavelength of antireflection was adjusted to further reduce the reflectance and enhance the spectral response of PERC cell in long wavelengths, in order to make the most of long-wavelength light transmitted through the perovskite top cell. Along with the increase of central wavelength, the external quantum efficiency of PERC cell at near-infrared wavelengths increases resulting in better short circuit current density and photoelectric conversion efficiency when filtered by the perovskite cell. A tandem efficiency gain of 0.07% (abs.) has been achieved. This report provides a facile way to improve the efficiency of perovskite/silicon four-terminal tandem solar cell based on the optimization of long-wavelength spectral response.

Multicrystalline silicon (mc-Si) PERC (passivated emitter and rear cell) solar cells suffer from severe light-induced degradation (LID), which mainly consists of two mechanisms, namely, BO-LID (boron&ndash, oxygen complex-related LID) and LeTID (light and elevated temperature induced degradation). The impact of thermal treatment on the LID of a mc-Si PERC solar cell is investigated in this work. The LID of mc-Si PERC solar cells could be alleviated by lowering the peak temperature of thermal treatment (namely sintering), perhaps because fewer impurities present in mc-Si tended to dissolve into interstitial atoms, which have the tendency to form LeTID-related recombination active complexes. The LID could also be effectively restrained by partially replacing the boron dopant with gallium, which is ascribed to the decreased amount of boron&ndash, oxygen (B&ndash, O) complexes. This work provides a facile way to solve the severe LID problem in mc-Si PERC solar cells in mass production.

Carbon nanotubes (CNTs) have attracted considerable attention due to their high aspect ratio, whisker-like form for best possible geometrical field enhancement, high electrical conductivity, and extraordinary thermal stability. Ion beam technology is a potential technique for controlled construction of CNTs. During collision with energetic ions, carbon atom of CNTs can get an adequate amount of energy to escape from the graphite lattice and produce a large number of defects. These defects are advantageous for adding some new functional groups and nanoparticles to modify CNTs. Meanwhile, the structure and atoms in the region of the defects can be rearranged and changed into amorphous structure, onion structure, and so on. These defects also can be used to form the junctions of CNTs and realize welding of CNTs and network formation of amorphous carbon nanowires.

Reactive ion etching technology was combined with passivated emitter & rear cell technology to reduce the reflectance and transmittance of incident light and improve the spectral response of polycrystalline silicon solar cell. Preconditioning with acid solution can induce the formation of worm-like structures on the front surface, which could bring about the reduction of reflectance and enhancement of spectral response in the visible range. Optimization of the capping layer thickness on the rear side can enhance the internal reflection, which will decrease the transmittance and promote the spectral response in long wavelength range.

Interfaces have a significant impact on the performance of perovskite solar cells. This work investigated the influence of hole transport material/metal contact interface on photovoltaic behaviours of perovskite solar devices. Different hole material/metal contact interfaces were obtained by depositing the metal under different conditions. High incident kinetic energy metal particles were proved to penetrate and embed into the hole transport material. These isolated metal particles in hole transport materials capture holes and increase the apparent carrier transport resistance of the hole transport layer. Sample temperature was found to be of great significance in metal deposition. Since metal vapour has a high temperature, the deposition process accumulated a large amount of heat. The heat evaporated the additives in the hole transport layer and decreased the hole conductivity. On the other hand, high temperature may cause iodization of the metal contact.

Through simulation with PC1D software, it comes to a conclusion that low reflectance is essential to realize better photovoltaic performance, especially Jsc. Therefore, MACE texturing technology and double-layer antireflection coating were employed to reduce the reflectance of DWS polycrystalline silicon wafer. In order to inhibit the higher surface recombination velocity induced by submicrostructure texture, thermally grown oxide was introduced to enhance the passivation quality of SiNx:H. Finally, compared with the solar cell fabricated with traditional acid-based etching method, an efficiency gain of up to 0.49% (abs.) has been achieved.

This paper mainly studied the correlation between the PID attenuation of P/N type bifacial cell and the adhesive film. At present, with the development of glass-glass module technology and bifacial cell technology, glass-glass bifacial module is an important direction of industry development. Currently P type monocrystal PERC bifacial cell and N-type PERT bifacial cell are typical representatives of the bifacial technology. However, the PID problem of bifacial cell is more serious than single side cell. How to solve the bifacial cell PID problem has become a hot topic. We mainly studied the correlation between two different adhesive film (EVA&POE), and the anti-pid attenuation ability of P/N type bifacial cell. The influence of the water vapor transmission rate and resistivity of the adhesive film on PID attenuation of bifacial cell was studied. After PID 192h test, For P type, power decay of the front side is lower than rear side, while for N type cell, power dacy of the rear side is lower than front side. Both P&N type bifacial cell module with POE are much better than with EVA. For POE, recipe adjustment affects PID performance obviously.