Single-crystal perovskite devices 2–3 mm thick exhibit 16.4% X-ray detection efficiency with sensitivity four times higher than α-Se X-ray detectors.

Sensitive X-ray detectors made of methylammonium lead tribromide perovskite single crystals

Organolead trihalide perovskite is an emerging low-cost, solution-processable material with a tunable bandgap from the violet to near-infrared, which has attracted a great deal of interest for applications in high-performance optoelectronic devices. Here, we present hybrid perovskite single-crystal photodetectors that have a very narrow spectral response with a full-width at half-maximum of <20 nm. The response spectra are continuously tuned from blue to red by changing the halide composition and thus the bandgap of the single crystals synthesized by solution processes. The narrowband photodetection can be explained by the strong surface-charge recombination of the excess carriers close to the crystal surfaces generated by short-wavelength light. The excess carriers generated by below-bandgap excitation locate away from the surfaces and can be much more efficiently collected by the electrodes, assisted by the applied electric field. This provides a new design paradigm for a narrowband photodetector with broad applications where background noise emission needs to be suppressed. Perovskite-based devices typically exhibit broadband spectral responses. Here narrowband (< 20 nm FWHM) response is achieved for a photodetector application.

Highly narrowband perovskite single-crystal photodetectors enabled by surface-charge recombination

Solar cell efficiency tables (version 57)

Solar cells based on inorganic absorbers, such as Si, GaAs, CdTe and Cu(In,Ga)Se2, permit a high device efficiency and stability. The crystals’ three-dimensional structure means that dangling bonds inevitably exist at the grain boundaries (GBs), which significantly degrades the device performance via recombination losses. Thus, the growth of single-crystalline materials or the passivation of defects at the GBs is required to address this problem, which introduces an added processing complexity and cost. Here we report that antimony selenide (Sb2Se3)—a simple, non-toxic and low-cost material with an optimal solar bandgap of ∼1.1 eV—exhibits intrinsically benign GBs because of its one-dimensional crystal structure. Using a simple and fast (∼1 μm min–1) rapid thermal evaporation process, we oriented crystal growth perpendicular to the substrate, and produced Sb2Se3 thin-film solar cells with a certified device efficiency of 5.6%. Our results suggest that the family of one-dimensional crystals, including Sb2Se3, SbSeI and Bi2S3, show promise in photovoltaic applications. Materials with a one-dimensional crystal structure, such as antimony selenide, show considerable potential for making efficient thin-film solar cells.

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Thin-film Sb2Se3 photovoltaics with oriented one-dimensional ribbons and benign grain boundaries

Solar cell efficiency tables (Version 55)

Atomic-layer-deposited aluminium oxide (Al2O3) is applied as rear-surface-passivating dielectric layer to passivated emitter and rear cell (PERC)-type crystalline silicon (c-Si) solar cells. The excellent passivation of low-resistivity p-type silicon by the negative-charge-dielectric Al2O3 is confirmed on the device level by an independently confirmed energy conversion efficiency of 20·6%. The best results are obtained for a stack consisting of a 30 nm Al2O3 film covered by a 200 nm plasma-enhanced-chemical-vapour-deposited silicon oxide (SiOx) layer, resulting in a rear surface recombination velocity (SRV) of 70 cm/s. Comparable results are obtained for a 130 nm single-layer of Al2O3, resulting in a rear SRV of 90 cm/s. Copyright © 2008 John Wiley & Sons, Ltd.

Surface passivation of high‐efficiency silicon solar cells by atomic‐layer‐deposited Al2O3

Laser contact openings for local poly-Si-metal contacts enabling 26.1%-efficient POLO-IBC solar cells

Working principle of carrier selective poly-Si/c-Si junctions: Is tunnelling the whole story?

We investigate the junction resistivity of high-quality carrier-selective polysilicon on oxide (POLO) junctions with the transfer length method. We demonstrate ${{n}}^{+ }$ POLO junctions with a saturation current density $J_{{\rm{C,poly}}}$ of 6.2 fA/cm2 and a junction resistivity $\rho _{{\rm{c}}}$ of 0.6 mΩcm2, counterdoped ${{n}}^{+ }$ POLO junctions with 2.7 fA/cm2 and 1.3 mΩcm2, and ${{p}}^{+ }$ POLO junctions with 6.7 fA/cm2 and 0.2 mΩcm2. Such low junction resistivities and saturation current densities correspond to excellent selectivities $S_{{10}}$ of up to 16.2. The efficiency potential for back-junction back-contact solar cells with these POLO junctions was determined to be larger than 25 % by numerical device simulations. We demonstrate experimentally a back-junction back-contact solar cell with p -type and n -type POLO junctions with an independently confirmed efficiency of 24.25 %.

Junction Resistivity of Carrier-Selective Polysilicon on Oxide Junctions and Its Impact on Solar Cell Performance

We demonstrate mask-free fabrication of a 22·0%-efficient crystalline Si solar cell by applying laser ablation of Si and by laser ablation of protective coatings. The bulk absorber material is a p-type float zone silicon wafer and the designated cell area is 4 cm2. While the processing time of our laboratory-type of laser system is far too slow for industrial processing, we estimate on the basis of our experiments that laser processing of 12·5 × 12·5 cm2-sized solar cells in just a few seconds is feasible with commercially available equipment. Copyright © 2006 John Wiley & Sons, Ltd.

Agnes Merkle

Papers

Surface passivation of high‐efficiency silicon solar cells by atomic‐layer‐deposited Al2O3

Laser contact openings for local poly-Si-metal contacts enabling 26.1%-efficient POLO-IBC solar cells

Working principle of carrier selective poly-Si/c-Si junctions: Is tunnelling the whole story?

Junction Resistivity of Carrier-Selective Polysilicon on Oxide Junctions and Its Impact on Solar Cell Performance

Laser structuring for back junction silicon solar cells