This study investigates the valorization of spent coffee grounds (SCGs) through protein extraction and their application in mycelium-based packaging and renewable energy pellets. Three extraction methods—mechanical stirring, ultrasound-assisted, and CO₂-assisted extraction—were applied to SCGs. CO₂-assisted extraction yielded the highest protein content at 34.24%, followed by mechanical stirring (31.46%) and ultrasound-assisted extraction (28.51%). The total polyphenol content and antioxidant capacity were also highest in the CO₂ extracts, suggesting that this method preserves bioactive compounds most effectively. After protein extraction, SCGs were tested as a component in mycelium-based packaging, with results showing an apparent density of 0.551 g/cm³ and compression resistance of 3.354 MPa, indicating its suitability for structural applications. The energy value of SCGs remained high, with a calorific value of 19,887 J/g DW, slightly decreasing after extraction but still sufficient for renewable energy production. These findings highlight the potential of SCGs as a multi-functional resource, contributing to sustainable solutions across various industries.

In this study, we investigate the impact of processing strategies on the nanoscale morphology and photophysical behavior of donor–acceptor thin films composed of the polymeric donor PBDTTTPD and the n-type acceptor PNDI(2HD)2T. The blend morphology and interfacial characteristics were systematically tuned using three distinct fabrication techniques: spin-coating, convective self-assembly, and space-confined solvent vapor annealing. Atomic force microscopy and photoluminescence spectroscopy were employed to elucidate structure–property correlations relevant to all-polymer optoelectronic systems. Films processed via convective self-assembly exhibited nanoscale features with extensive donor–acceptor intermixing, leading to the most efficient photoluminescence quenching of nearly 85%, indicative of enhanced exciton dissociation and charge transfer. In contrast, as-cast films displayed moderately mixed morphologies with approximately 81% quenching, serving as a reference state. The solvent vapor annealing method induced pronounced phase segregation and the formation of larger domains, resulting in reduced photoluminescence quenching efficiency of about 52%. These findings demonstrate that the nanoscale morphology, and consequently the photophysical response, of PBDTTTPD:PNDI(2HD)2T blends can be precisely tailored through processing, providing valuable design guidelines for all-polymer optoelectronic applications such as organic photovoltaics and field-effect transistors.