The electroluminescence quantum efficiency roll-off in iridium(III)-based complexes, namely Ir(iqbt)₂(dpm) and Ir(iqbt)₃ (iqbt = 1 (benzo[b]thiophen-2-yl)-isoquinolinate, dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate) utilized as near-infrared emitters in organic light emitting diodes with remarkable external quantum efficiencies, up to circa 3%, 1.5% and 1%, are measured and analyzed. With a 5–6 weight% of emitters embedded in a host matrix, the double-layer solution-processed structure as well as analogous three-layer one extended by a hole-conducting film are investigated. The triplet-polaron, the Onsager electron-hole pair dissociation and the triplet-triplet annihilation approaches were used to reproduce the experimental data. The mutual annihilation of triplets in iridium emitters was identified as prevailingly controlling the moderate roll-off, with the interaction between those of iridium emitters and host matrixes found as being less probable. Following the fitting procedure, the relevant rate constant was estimated to be $\left(0.5-12\right)\times {10}^{-12}$ cm³/s, values considered to be rather too high for disordered organic systems, which was assigned to the simplicity of the applied model. A coexistence of some other mechanisms is therefore inferred, ones, however, with a less significant contribution to the overall emission quenching.

Two types of full-size photovoltaic modules for on-grid systems with maximum DC voltage of 600 V have been developed and prepared for production. With carefully selected materials and dedicated manufacturing processes the weight of 3.5 and 3.2 kg, the power as high as 220 and 200 Wp and efficiencies of 20.1 and 21.3% were obtained. Together with standard mounting systems the devices make it possible to build non- intrusive installations on low-load capacity roofs with various types of covering, particularly in large-scale lightweight buildings.