This talk will highlight our recent work on bio-inspired surface treatments to control reflection at interfaces. An easy, scalable and defect-tolerant surface modification protocol, based on colloidal lithography and plasma etching, was developed to create synthetic 'moth-eye' (ME) anti-reflective structures in different material platforms for photonics and energy applications. Large increases in transmission, bandwidth, and omni-directional response were obtained in Si, Ge, GaAs, and CdTe platforms for IR (2-50+ microns), with performance better than commercial, interference-based coatings. ME coatings were also implemented in blue-green InGaN/GaN quantum well LED structures to enhance light extraction and device efficiency. Effective medium theory, finite difference time domain (FDTD) simulations, and quantitative measurements of transmission, reflection and diffuse scattering were used to understand the ‘photon balance’ of moth-eye films to investigate how optical behavior depends on moth-eye geometry, (dis)order, and pattern fidelity.