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We have developed a microcrystalline silicon oxide (μc-SiOx:H) p-type emitter layer that significantly improves the light incoupling at the front side of silicon heterojunction solar cells by minimizing reflection losses. The μc-SiOx:H p-layer with a refractive index of 2.87 at 632 nm wavelength and the transparent conducting oxide form a stack with refractive indexes which consecutively decrease from silicon to the ambient air and thus significantly reduce the reflection. Optical simulations performed for flat wafers reveal that the antireflective effect of the emitter overcompensates the parasitic absorption and suggest an ideal thickness of about 40 nm. On textured wafers, the increase in current density is still more than 1 mA/cm² for a typical emitter thickness of 10 nm. Thus, we are able to fabricate heterojunction solar cells with current densities significantly over 40 mA/cm² and power conversion efficiency above 20%, which is yet mainly limited by the cell's fill factor. [ABSTRACT FROM AUTHOR]

Abstract To make the concept of building-integrated solar cells viable, the latter should possess an increased tolerance towards light incident angle and intensity that naturally change along the day, among other required properties. In this work, three solar cell technologies as candidates for building-integrated applications are compared regarding their normalized average efficiency as a function of light intensity and incident angle. The mechanisms that lead to higher efficiency independence are evidenced by comparing several cell designs for dye-sensitized solar cells (DSC) and perovskite solar cells (PSC). By doing so, it was found that superior efficiency independence towards tilted light is obtained for PSC with more transparent active layers due to optical path lengthening (OPL), while DSC were found to exhibit OPL in standard configuration. All cells show a fairly stable efficiency evolution when light intensity was reduced, while at lower light intensity PSC slightly outperform DSC. The almost constant relative efficiency evolution of silicon heterojunction (SHJ) solar cells is a very interesting outcome of this work and so far, efficiency evolution of such SHJ under low light intensity have not been reported in the literature to the best of our knowledge. Graphical abstract fx1 Highlights • Optical path lengthening under angle variation causes > cos(θ) evolution in DSC. • Similarly behaving thinner PSC are interesting for building-integrated concepts. • All cell types show a quite stable efficiency evolution until 0.4 sun. • SHJ cells reveal as very interesting candidates for low-light applications. [ABSTRACT FROM AUTHOR]

Hydrogenated nanocrystalline silicon oxide (nc-SiO x :H) films have demonstrated a unique combination of low parasitic absorption and high conductivity. Here, we report on the use of n-type nc-SiO x :H as front surface field (FSF) in rear-emitter silicon heterojunction (SHJ) solar cells exhibiting excellent electrical cell parameters at a thickness down to only 5 nm. Using a seed layer, we are able to maintain excellent electrical performance (high fill factor ( FF ) and open circuit voltage ( V OC )), while enhancing layer transparency for maximizing short circuit current ( J SC ). These results, together with the short deposition time (< 100 s), make the (n)nc-SiO x :H FSF attractive for reducing production costs in industrial applications. The best device, with the optimized (n)nc-SiO x :H FSF layer, shows V OC of 731 m V , FF of 80.6%, J SC of 38.3 mA/cm 2 and a power conversion efficiency of 22.6%. [ABSTRACT FROM AUTHOR]

We report here on the development of a rear-side point-contact scheme for liquid-phase-crystallized silicon on glass solar cells, which uses laser for all structuring and contact-post-treatment steps. Our contact scheme is based on the procedure developed by CSG Solar and contains two main innovations. First, we demonstrate here that it is possible to form contact holes in the back-reflector resist layer by laser ablation instead of printing droplets of an etch solution with inkjet. The use of laser for forming holes in the resist holds promise for enhancing the precision and reliability of this process. Second, we show that for both p and n-type absorbers, laser firing at the absorber-point-contacts can be used to increase the doping concentration beneath the metal contact and thereby achieve low-resistance contacts. Using the All-by-Laser Point-contact Scheme (ALPS) we were able to reach a solar cell conversion efficiency of 11.5% for a planar n-type laser-crystallized silicon absorber with an amorphous/crystalline heterojunction structure. [ABSTRACT FROM AUTHOR]