Highly efficient luminescence from a hybrid state found in strongly quantum confined PbS nanocrystals

We report that high quality PbS nanocrystals, synthesized in the strong quantum confinement regime, have quantum yields as high as 70% at room temperature. We use a combination of modelling and photoluminescence up-conversion to show that we obtain a nearly monodisperse size distribution. Nevertheless, the emission displays a large nonresonant Stokes shift. The magnitude of the Stokes shift is found to be directly proportional to the degree of quantum confinement, from which we establish that the emission results from the recombination of one quantum confined charge carrier with one localized or surface-trapped charge carrier. Furthermore, the surface state energy is found to lie outside the bulk bandgap so that surface-related emission only commences for strongly quantum confined nanocrystals, thus highlighting a regime where improved surface passivation becomes necessary

Magneto-optical spectroscopy of charged CdSe nanocrystals

International audienc

Protocol of a randomised controlled multicentre trial investigating the effectiveness and safety of a wilderness programme on the mental and physical well-being of adolescents and young adults affected by cancer : the WAYA-2 study

INTRODUCTION: Adolescents and young adults (AYAs) affected by cancer are an understudied group. Effective interventions are needed to support coping with the late effects of cancer, its treatment and to promote quality of life. Nature-based interventions may be promising in support of the self-management and health of AYAs affected by cancer. However, randomised controlled studies (RCTs) on the effectiveness of such interventions are lacking. We performed a first pilot RCT (n=42) that showed that it is feasible and safe to conduct such a study. Here, we propose a full-scale RCT to investigate the effectiveness and safety of a wilderness programme on the mental and physical health of AYAs affected by cancer. METHODS AND ANALYSIS: Participants are 150 AYAs affected by cancer, aged 16-39 years, who will be randomised to a wilderness (n=75) or a hotel stay (n=75). The wilderness programme is an 8-day intervention including a 6-day wilderness expedition. This is followed 3 months later by a 4-day intervention including a 2-day basecamp. Activities include hiking, backpacking, kayaking, rock climbing, mindfulness and bush-crafting. The comparison group is an 8-day hotel stay followed by a 4-day hotel stay (interventions include two travel days) at the same hotel after 3 months. Primary outcomes are psychological well-being and nature connectedness up to 1 year after the study start. Secondary outcomes are quality of life, physical activity and safety parameters. ETHICS AND DISSEMINATION: The Swedish Ethical Review Authority approved the study protocol on 27 September 2023 (reference: 2023-05247-01). The recruitment started on 19 February 2024 and the first part is planned to end on 31 December 2027. Study results will be disseminated by means of scientific publications, presentations at conferences, popular articles, interviews, chronicles and books. News items will be spread via social media, websites and newsletters. TRIAL REGISTRATION NUMBER: ISRCTN93856392

Synthesis of PbS/CdS core-shell QDs and their nonlinear optical properties

10.1021/jp104311jJournal of Physical Chemistry C1144218037-1804