Molecular Optimization Enables over 13% Efficiency in Organic Solar Cells

Abstract

A new polymer donor (PBDB-T-SF) and a new small molecule acceptor (IT-4F) for fullerene-free organic solar cells (OSCs) were designed and synthesized. The influences of fluorination on the absorption spectra, molecular energy levels, and charge mobilities of the donor and acceptor were systematically studied. The PBDB-T-SF:IT-4F-based OSC device showed a record high efficiency of 13.1%, and an efficiency of over 12% can be obtained with a thickness of 100-200 nm, suggesting the promise of fullerene-free OSCs in practical applications.

An Alkylated Indacenodithieno[3,2‐b]thiophene‐Based Nonfullerene Acceptor with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies Greater than 13% with Low Voltage Losses

“…Among the highest performing NFAs, linear rod-like acceptor-donor-acceptor (A-D-A) structures incorporating fused ladder-type aromatics have attracted much interest. Common donor units include 4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene (IDT) [5][6][7][8][9] and 6,12-dihydro-dithienoindeno [10][11][12][13][14][15][16][17][18] In both cases, the fused core facilitates π-electron delocalization and improves the π-π stacking between molecules, hence enhancing the intrinsic charge carrier mobility.In 2015, Zhan and coworkers reported a new NFA, 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11--b′]dithiophene (ITIC) (Scheme 1), which is comprised an electron-donating IDTT-based core flanked by two electron-withdrawing units of 1,1-dicyanomethylene-3-indanone (IC), that exhibited a promising PCE of 6.8% at that time. [10] Since then, many strategies have been applied to modify the structure of ITIC in order to adjust the absorption spectra and energy levels to further improve the PCE, for example, by changing the side chains, [17,18] extending the conjugation length, [19][20][21][22] and substituting the end acceptor groups.…”

“…Among the highest performing NFAs, linear rod-like acceptor-donor-acceptor (A-D-A) structures incorporating fused ladder-type aromatics have attracted much interest. Common donor units include 4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene (IDT) [5][6][7][8][9] and 6,12-dihydro-dithienoindeno [10][11][12][13][14][15][16][17][18] In both cases, the fused core facilitates π-electron delocalization and improves the π-π stacking between molecules, hence enhancing the intrinsic charge carrier mobility.…”

“…[13][14][15][16] To date, a few systems based on these NFAs have achieved a PCE of over 10%. [5,[13][14][15]18,20,22] However, it is noticeable that in all cases these NFAs incorporate phenylalkyl or thienylalkyl side chains as the solubilizing groups on the fused core. These aryl-based side chains facilitate the synthesis of the IDTT core under Friedel-Crafts conditions via the formation of stable triaryl cations.…”

Environmentally-friendly solvent processed fullerene-free organic solar cells enabled by screening halogen-free solvent additives

“…The ZnO precursor was prepared by dissolving zinc acetate dihydrate and ethanolamine in 2-methoxyethanol, and the ZnO precursor solution was spin-cast on the top of ITO substrates. The substrates were annealed at 200°C for 1 h [57]. The condition of blend film based on PBDB-T:IT-M in inverted OSCs is the same with that used in the conventional OSCs.…”

Charging Characteristics of Lithium Ion Battery Using Semi-Solar Modules of Polymer:Fullerene Solar Cells

“…To date, most research on PSCs has been focused on the enhancement of power conversion efficiency (PCE), while device stability has recently attracted keen interest because the PCE has been encouragingly improved up to >10% [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. In order to examine the potential of PSCs, however, practical approaches to utilizing PSCs are of crucial importance for further improvement.…”