In photovoltaics many efforts are being dedicated towards efficient management of light. As listed by Wang and Qi, different light management strategies have been demonstrated so far, Figure , where self-assembly can be quite advantageous for the fabrication process and the required structural complexity. One such strategy is the fabrication of an anti-reflection coating for efficient light trapping before reflection losses. Shimomura et al. demonstrated the fabrication of such anti-reflection coating by electrostatic layer-by-layer assembly of 15 nm silica (SiO2) and 7 nm TiO2 nanoparticles that showed significant decrease in reflection with an increasing number of layers, Figure ). Such anti-reflection coating can significantly enhance the photovoltaic efficiency . Efficiency enhancements of 11% to 12.3% have been reported for Si solar cells coated with selfassembled silica nanospheres. Apart from the reduction in surface reflectance in the UV and IR regions, silica nanospheres are also thermal shock resistant and chemically inert. Chang et al., on the other hand, showed an efficiency enhancement of 25% by the use of a scattering enhancing coating made of self-assembled polystyrene microspheres, Figure ). These 2D polystyrene sphere layers were obtained on the top surface of a GaAs solar cell. The scattering of the microspheres enhances the path length of the incident light. Self-assembled layers of other dielectric nanoparticles such as alumina, silica, etc., can also enhance the performance of solar cells by scattering of incident light, increasing active layer absorption and photocurrent output. While thin film solar cells usually have a hierarchical structure with stacks of planar films, self-assembly facilitates complex patterning in these films. For instance, self-assembled polystyrene nanosphere multi-layers can be used as a sacrificial template so that the semiconductor material can fill the interstitial voids before the template is removed. This approach was demonstrated by Guldin et al. to obtain inverse TiO2 opal or hollow structures (Figure ) that result in 10% enhancement in the photocurrent. The slow light effect of photonic crystals is also an important physical aspect that is known to enhance both photovoltaic and photocatalytic processes. In inverse opal structures as shown in Figure , the slow light effect can also significantly enhance the photovoltaic efficiency. In thermophotovoltaics, nanostructures for selective thermal emission can also be obtained by self-assembly. As shown by Arpin et al., 3D tungsten photonic crystals obtained by selfassembled templates have unprecedented thermal stability up to 1400 o C and modified thermal emissions. Also, with self-assembled photonic crystals of hafnium diboride it is demonstrated that refractory metallic ceramic materials are viable candidates for photonic crystal-based solar thermophotovoltaic devices. In many instances, plasmonic nanoparticles have been shown as the light-trapping components in a line of work often referred to as plasmonic photovoltaics. As plasmonic nanoparticles are intense light absorbers, more light is trapped by such nanoparticles and potentially leading to hot electron generation. It is postulated that the hot electrons from the plasmonic metal are injected into the semiconductor and holes migrate to the counter electrode through the hole transport material. When these plasmonic nanoparticles are obtained as closed packed films, the inter-particle coupling enhances the light-matter interaction even further. Reineck et al. showed that self-assembled Au and Ag nanoparticles can be combined with TiO2 photovoltaic films to get photocurrents that are much higher than those obtained for dye sensitized solar cells, Figure . Also, the nanoparticles are much more stable over time compared to organic dyes. Reprinted with permission © 2019 John Wiley & Sons. (b) Anti-reflection coatings obtained by layer-by-layer self-assembly of silica and titania nanoparticles. Reprinted with permission © 2010, American Chemical Society (c) Self-assembled polystyrene spheres on GaAs solar cells significantly enhance the current density by multiple scattering and optical path elongation. © 2009 Optica Publishing Group (d) The use of multi-layer self-assembled polystyrene nano/microspheres as sacrificial templates results in porous networks of TiO2, when TiO2 is crystallized in the interstitial voids and the polystyrene is removed, Such inverse opal structures have a strong slow light effect. Reprinted with permission © 2010, American Chemical Society (e) The plasmonic enhancement in solar cells can be further improved using self-assembled films of plasmonic nanoparticles that are coupled electrodynamically to result in stronger light-matter interactions. Plasmonic solar cells show higher photocurrents and stability over time than organic dye sensitized cells. Reprinted with permission © 2012 John Wiley & Sons.