The use of electronic devices with blue-enriched light for reading, communication, and entertainment has increased immensely – especially in children and adolescents. Accumulating empirical evidence indicates that blue light exposure before going to bed disturbs sleep function. Therefore, we are interested in whether sleep-related memory consolidation processes are affected by blue light exposure during bedtime in an adolescent population. The main objective of this project is to focus on three research questions: (1) Does blue light exposure (via smartphone) before falling asleep affect sleep physiology (sleep spindles, slow oscillations, REM) and, consequently, is there a protective effect of orange filter screens on sleep?; (2) Is smartphone light powerful enough to initiate changes in circadian timing (melatonin/cortisol secretion and body temperature)?; and (3) Does smartphone blue light impact consecutive sleep-dependent declarative memory consolidation (as there is a disturbance/change in sleep physiology) as well as affective functioning?