Low cost nanostructured antimony selenide for embedded energy systems

越来越多的小型便携式/远程系统，从医疗应用中的生物传感器到城市环境中的“物联网”，需要可持续的高产量离网能源自主。设计灵活性和低成本材料需要成为此类嵌入式能源系统中考虑的重要组成部分。光子提供了一个合适的和广泛可用的能源，它可以被有效地收集，操纵和引导到亚微米尺度。硒化锑（Sb 2Se 3）是一种新兴的地球丰富的材料，具有非常好的光伏（PV）特性（即，高光吸收系数和接近最佳带隙）。Sb 2Se 3晶体生长成带状结构，导致沿着[001]方向具有改善的载流子输运的1D结构，然而据报道，这种PV器件的性能受到缺陷的限制。可以设想，通过形成自组装纳米结构阵列，光子晶体，例如使用氧化锌纳米棒，光可以有效地分布到共形的极薄吸收体，具有增加收集面积和降低对电子扩散长度的要求的益处。在诺森比亚大学，基于Sb 2Se 3材料的平面PV器件通常通过热蒸发以约2.8%的转换效率制造，形成基线装置。在本项目中，将开发一种替代的低成本制造工艺，该工艺基于水热或替代溶液工艺，以生产纳米结构材料（即纳米颗粒、纳米线或纳米管）。这种方法将确保吸收体材料的制造与其在非平面衬底上的共形沉积（例如，在光波导上的预成型光子晶体）的解耦。表面载流子复合减少将通过界面工程通过ALD沉积单层氧化物（例如TiO 2或Al 2 O 3）进行研究。为了确保高密度的光子到达吸收材料，将设计合适的光学和光波导系统。将在一系列嵌入式能源系统中，在理论（例如COMSOL）和实验设计原型之间进行性能比较。

Increasingly, small portable/remote systems, from biosensors in medical applications to "internetof things" in urban environments, require sustainable high yield off-grid energy autonomy. Designflexibility and low cost materials need to be an integral part for consideration in such embeddedenergy systems. Photons offer a suitable and widely available source of energy, which can beefficiently collected, manipulated and guided down to sub-micron scale. Antimony Selenide(Sb2Se3) is an emerging Earth abundant material with very good photovoltaic (PV) characteristics(i.e. high optical absorption coefficient and near optimum band gap). Sb2Se3 crystals grow inribbon-like structures resulting in 1D structures with improved carrier transport along the [001]direction, it is however reported that performance of such PV devices are limited by defects. It canbe envisaged that by forming a self-assembled nanostructure array, a photonic crystal, such asusing zinc oxide nanorods, light can be efficiently distributed towards a conformal extremely thinabsorber with the benefit of increased collection area and reduced requirement on the electrondiffusion length.At Northumbria University, planar PV devices based on Sb2Se3 materials are routinely fabricatedby thermal evaporation with ~2.8% conversion efficiency, forming a baseline device. In thisproject, an alternative low cost fabrication process will be developed based on hydrothermal oralternative solution based processes, to produce nanostructured materials (i.e. nanoparticles,nanowires or nanotubes). This method will ensure decoupling of the absorber materialsfabrication from its conformal deposition onto non-planar substrates (e.g. pre-formed photoniccrystals onto optical waveguide). Surface carrier recombination reduction will be studied throughinterface engineering via the deposition of monolayer oxides by ALD (e.g. TiO2 or Al2O3). Toensure high density of photons are reaching the absorber material, suitable optics and opticalwaveguides system will be designed. A comparison in performance will be made in a range ofembedded energy system, between theoretical (e.g. COMSOL) and experimental designedprototypes.