ABSTRACT
In near-infrared (NIR) polymer phototransistors, the photoresponse is proportional to the turn-on voltage shift (ΔVth). Due to the narrow band gap of NIR polymers, the ΔVth value is usually small. However, the use of a single bulk heterojunction (BHJ) layer has a minimal effect on increasing the value of ΔVth. This is because doping with high concentrations of acceptors results in strong current traps and accelerates electron/hole recombination. In this work, a new strategy is proposed to control the recombination of electrons/holes. By doping an insulating medium made of polystyrene (PS) into BHJs, PC61BM:PS:PDPP3T-based ternary NIR phototransistors with high acceptor concentrations were prepared by using a one-step film transfer method (FTM). Compared with a PC61BM:PDPP3T-based binary device (1:1), a ternary device (1:1:1) exhibited a significant performance improvement. The ΔVth value (â¼29.5 ± 1.0 V) increased by approximately 4-fold, the Iph/Idark (â¼4.4 × 106) increased by a factor of 3000 to 4000-fold, and the dark current decreased by 2-3 orders of magnitude (@ Vg = 0 V). Additionally, the ternary devices demonstrated excellent performance across a wide ternary ratio range (1:1:1 to 4:2:1).
ABSTRACT
Purpose: The rise of the opioid epidemic coincided with the increased risk of suicide as the leading causes of death among adolescents in the United States. Past research has linked non-medical prescription opioid use (NMPOU) with adolescent suicide. Less focus has been placed on race and ethnic differences among adolescents impacted by the opioid epidemic. This study examined the relationship of adolescent NMPOU and suicidality, stratified by race. Method: The 2016 National Survey on Drug Use and Health (NSDUH) was used for this study. Weighted multivariate logistic regression analyses were conducted on a sample of 11,489 adolescent respondents to examine the effect of past-year NMPOU with the odds for serious thoughts of suicide, having a suicide plan, and making a suicide attempt. Results: Findings indicated a higher prevalence of suicidality among adolescents who engaged in NMPOU compared to non-users. Adolescent opioid misuse was associated with 68% higher odds for having a suicide plan in the past year (OR = 1.68, 95% CI: [1.07, 2.63], p < 0.05). Interaction analysis found that among Asian adolescents, NMPOU was associated with higher odds for having a suicide plan compared to other race groups (OR=1.53, 95% CI: [1.04, 2.23], p < 0.05). Discussion: Results indicated that adolescent opioid misuse is a risk factor for suicide, and Asians compared to other race groups were at greater risk. Social workers can serve as a nexus point in effectively engaging at-risk adolescents in substance use and mental health prevention and recovery services.
