Antimony sulfide (Sb2S3) is a promising photoelectric material because of its wide bandgap approximately 1.7 eV for next‐generation solar cells, high optical absorption coefficient, and its green and earth‐abundant constituents. Different to traditional cubic structure photovoltaic materials, Sb2S3 holds one‐dimensional crystal structure and its thin film with [hk1] preferred orientation shows one‐order‐higher carrier transport mobility. However, all the reported Sb2S3 films exhibited [hk0] preferred orientation on CdS‐based superstrate device structure up to now. Thus, it is indispensable to study the controllable‐orientations Sb2S3 film deposition and the relationship between the orientation and performances. In this paper, we develop a vertical vapor transport deposition (V‐VTD) method, which can tune the preferred orientation of Sb2S3 thin film from [hk0] to [hk1] by reaction recipe monitoring. Combining the experiment results, a reasonable deposition/reevaporation competing model is suggested to explain above orientation conversion mechanism. The device efficiency increases from less than 2% to about 4% with the orientation of Sb2S3 film changing from [hk0] to [hk1]. By fine regulating the technique of deposition, the device with [hk1] orientation has better crystallinity, lower interface recombination, and higher built‐in voltage comparing with the [hk0] one. Finally, a champion power conversion efficiency (PCE) of 4.5% has been achieved, and the VOC of 730 mV is the top value among the Sb2S3 solar cells. The present versatile orientation tuning strategy could overcome the bottleneck of strong anisotropic materials and show high potential for noncubic material deposition and related optoelectronic device performance enhancement.
Taking raw coal and briquette coal samples with preset center holes as research objects, this paper makes a systematic analysis and research of crack evolution laws of the two different coal samples under the local load. The results show that the raw coal and briquette coal samples are different mainly in number, dimension, and complexity of the internal microstructures, so it is not right to replace raw coal with briquette coal when performing observational study of the crack evolution of microstructures; under the effect of local load, local property, randomness of crack initiation position, and crack initiation stress of raw coal samples are greater than those of briquette coal samples; law of instantaneous maximum effective cut-through rate of raw coal samples is more complex than that of briquette coals; under the effect of uniformly distributed load, end effect factor Fe, sample microstructure influencing factor Fs, and preset center hole factor Fh are the major factors influencing crack growth, among which the amplified end effect factor Fe and sample microstructure influencing factor Fs are dominant factors; under the effect of local load, local load influencing factor Fp, end effect factor Fe, sample microstructure influencing factor Fs, and preset center hole factor Fs are the major factors influencing crack growth, among which the local load influencing factor Fp, end effect factor Fe, and sample microstructure influencing factor Fs are dominant factors. Compared with briquette coal samples, raw coal samples are more sensitive to influencing factors, such as local load influencing factor Fp, end effect factor Fe, sample microstructure influencing factor Fs, and preset center hole factor Fh, and can aggravate the influence of these factors on the crack growth; the paper also puts forward a method for describing local load based on a coupling mechanical model of uniaxial compression and local shear.
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