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Organic solar cells (OSCs) based on ADA-type (acceptor-donor-acceptor) non-fullerene acceptors (NFAs) exhibit improved power conversion efficiency (PCE) compared to the conventional fullerene-based analogues. The optoelectronic properties of OSC active layer blends are correlated to their underlying structural dynamics and therefore influence the device performance. Using synergistically different neutron spectroscopy techniques, we studied the dynamics of binary and ternary blends made of the NFAs O-IDTBR and O-IDFBR and the regioregular donor polymer P3HT. Deuteration was considered for a contrast variation purpose. In addition to shedding light on the miscibilty and alloying characters of the blends, a main outcome of this work is the evidenced similar dynamical response of the blend components. This finding is in contrast with our previous neutron spectroscopy and molecular dynamics studies of the fullerene-based blend P3HT:PCBM, where we highlighted distinct behaviors of P3HT and PCBM in terms of the vitrification/frustration of P3HT and the plasticization of PCBM by P3HT upon blending. Alike P3HT vitrification is not presently observed. The absence or the weak vitrification evidenced here is in line with recent reports and is likely related to the improved PCE exhibited by the ADA-type NFA-based OSCs.

We present a neutron spectroscopy based method to study quantitatively the partial miscibility and phase behaviour of an organic photovoltaic active layer made of conjugated polymer:small molecule blends, presently illustrated with the regio-random poly(3-hexylthiophene-2,5-diyl) and fullerene [6,6]-Phenyl C$_{61}$ butyric acid methyl ester (RRa-P3HT:PCBM) system. We perform both inelastic neutron scattering and quasi-elastic neutron scattering measurements to study the structural dynamics of blends of different compositions enabling us to resolve the phase behaviour. The difference of neutron cross sections between RRa-P3HT and PCBM, and the use of deuteration technique, offer a unique opportunity to probe the miscibility limit of fullerene in the amorphous polymer-rich phase and to tune the contrast between the polymer and the fullerene phases, respectively. Therefore, the proposed approach should be universal and relevant to study new non-fullerene acceptors that are closely related - in terms of chemical structures - to the polymer, where other conventional imaging and spectroscopic techniques present a poor contrast between the blend components.

We present a detailed study of the structure-dynamics relationship of regio-regular and regio-random PEHT using different neutron scattering techniques. Deuteration is employed to modulate the coherent and incoherent cross-sections, allowing particularly to access both self-motions and collective dynamics of the materials. The measurements are underpinned by extensive quantitative calculations using classical MD, as well as first principles quantum chemistry. MD reproduced well the main structural features and slow motions, and shed light on differences in collective dynamics between Q-values linked with the $\pi-\pi$ stacking and the lamellar stacking, with the crystalline phase being the most impacted. On the other hand MD led to a limited description of molecular vibrations. In this context, first principles molecular calculations described well the high-energy vibrational features ( $>$ 900 cm$^{-1}$ ), while periodic calculations allowed to better describe the low- and mid-energy vibrational ranges ( 200-900 cm$^{-1}$ ). The mid-energy range is predominantly associated with both intra-molecular and inter-molecular mode coupling, which encloses information about both the polymer conformation and the polymer packing at short range. One of the outcomes of this study is the validation of the common assumption made that RRa-P3HT is a good approximation for the amorphous phase of RR-P3HT at the macroscopic level. The present work helps to clarify unambiguously the latter point which has been largely overlooked in the literature. We highlight the importance to complement optical spectroscopy techniques with inelastic neutron scattering. The latter offering the advantage of being insensitive to the delocalized $\pi$-electron system, and thus enabling to infer relevant quantities like conjugation lengths, for instance, impacting properties of conjugated polymer., Comment: Featured as ACS Editors' Choice. Featured on the Cover of the December 10, 2019 issue of Chemistry of Materials

There has been a growing interest in placing sworn police officers in schools as SROs to improve school safety. The purpose of the National Assessment was to identify what program "models" have been implemented, how programs have been implemented, and what the programs' possible effects may be. To obtain this information, Abt Associates conducted a nationwide survey of established and relatively new SRO programs and collected implementation data from 19 SRO programs. This report describes the activities the project team conducted for the National Assessment and summarizes the study findings. The report has five sections, which follow the chronology of the project: (1) Mail Survey--a summary of the methodology and findings of the first significant project task; (2) Selection of Study Sites--a review of the site selection criteria and the sites selected; (3) The Site Visits--a description of the preparation for, goals, and conduct of the site visits; (4) Modifications to the Research Methodology--a description of the change from an outcome study to a process evaluation for the large new sites and the reasons for the change; and (5) Data Analysis and Findings--a summary of the methodology and findings of the five other reports prepared under the project. The report concludes with appendices providing protocols and other materials used in the project. Appended are: (1) Principal Materials Examined for the Study; (2) Mail Survey of Law Enforcement Agencies; (3) Mail Survey of School Principals; (4) Site Visit Preparation Protocol; (5) Program Participation Interview Guide; and (6) Survey of Students: Large New Programs. [Appendixes are not included in ERIC version of this report.]

There has been a growing interest in placing sworn law enforcement officers in schools as School Resource Officers (SROs) as a means of improving school safety and improving relations between police officers and youth. However, when this project began in May 2000, relatively little was known about SRO programs. The purpose of the National Assessment was to identify what program "models" have been implemented, how programs have been implemented, and what lessons they may have for other programs. To obtain this information, Abt Associates and its subcontractors collected implementation data by telephone and on site from 19 SRO programs. This information forms the basis of this case studies report. The report begins with a separate case study of each of the five large established programs. Each case study begins with a capsule description of the program followed by a detailed account of its context, history, and operations. Although all five large established programs serve multiple schools, within four of these five programs the researchers singled out a single school for intensive study based on the recommendation of the program supervisor. As a result, much of the information in these four case studies is based on the experience of a single school. (Contains 6 Appendices.)

There has been growing interest in placing sworn law enforcement officers in schools as School Resource Officers (SROs) to improve school safety and improve relations between police officers and youth. The purpose of this National Assessment was to identify what program "models" have been implemented, how programs have been implemented, and what lessons selected programs may have for other programs. To obtain this information, Abt Associates and its subcontractors collected implementation data from 19 School Resource Officer programs. This cross-site report discusses commonalities and differences among the 19 sites with a particular focus on lessons learned--information based on the experience of the sites that can benefit other jurisdictions in setting up or improving an SRO program. The report focuses on seven issues: (1) Choosing a Program Model; (2) Defining Specific SRO Roles and Responsibilities; (3) Recruiting SROs; (4) Training and Supervising SROs; (5) Collaborating with School Administrators and Teachers; (6) Working with Students and Parents; and (7) Evaluating SRO Programs.

A review of the literature and interviews with over 50 people in the field revealed that job-related stress is widespread and possibly increasing among correctional officers. This publication is intended to help correctional administrators develop an effective program for preventing and treating correctional officers' stress. A variety of approaches are described for relieving officers' stress. Seven case studies of well-established and replicable stress programs are presented. Establishing such programs have many benefits such as: (1) reducing overtime costs incurred when officers take sick time or quit because of job-related stress; (2) improving officer performance by enhancing staff morale; (3) increasing institutional safety by reducing distractions caused by stress; (4) improving relations with the union by working together; and (5) showing concern for employees by demonstrating that department cares about staff as human beings. Correctional and sheriff's departments need to address several considerations to make their programs effective such as: appoint staff who can stand the stress of helping others who experience stress; work collaboratively with administrators, union officers, and family members; maintain confidentiality; and monitor program activities and evaluate their effectiveness. (Contains 10 exhibits and 9 appendixes.) (JDM)

Since 1976, the Correctional Clearinghouse (CCH), which is a unit of the Washington State Employment Security Department, has been committed to preparing offenders for the workplace and finding employment. The CCH's principal service delivery strategies are as follows: (1) providing direct services (teaching job readiness courses in prisons and contracting with community-based organizations to provide job search assistance to ex-offenders); (2) brokering services available from other agencies (helping a community college and state agency establish a for-credit college program integrating job search assistance with substance abuse treatment for ex-offenders in recovery); and (3) coordinating activities across agencies (arranging for inmates to produce and distribute the statewide computerized Case Management Resource Directory). CCH's continuum of services to prisoners, which begins with employability assessment during incarceration and ends with job placement and ongoing assistance after employment, has proved highly successful. In 1997-1998, at least 3,080 inmates completed a CCH employment or training activity in 5 of Washington's 15 correctional institutions. Of the 1,312 ex-offenders who received job search assistance through the CCH in 1996-1997, 776 were placed in jobs and 68% were still in those jobs after 45 days. (Seven sources of assistance in replicating the CCH model are listed.) (MN)