Hydrogen Bond Induced Green Solvent Processed High Performance Ternary Organic Solar Cells with Good Tolerance on Film Thickness and Blend Ratios

Abstract

For comprehensive development of organic solar cells (OSCs), some factors such as environmental stability, low cost, insensitive film thickness, component contents tolerance, and green preparation processes are equally crucial to achieve high power conversion efficiencies (PCEs). In this work, a small molecule 3-(diethylamino)-7-imino-7H-benzo[4,5]imidazo[1,2-a]chromeno[3,2-c]pyridine-6-carbonitrile (DIBC), which is commercially available at low cost, is utilized to realize high-performance ternary OSCs. Demonstrated via Fourier transform infrared and 2D-1 HNMR, DIBC can form hydrogen bond interactions with [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM) in solid films. Further electrostatic potential (ESP) calculations indicate that the hydrogen bond interaction enhances the ESP of PC 71 BM and accelerates charge transport between donor and acceptor. As a result, poly(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl) benzo[1,2-b;4,5-b0]dithiophene-2,6diylalt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl(PTB7-Th):DIBC:PC 71 BM-based ternary OSC achieves a maximum efficiency of 12.17%, which is the best result of green solvent processed fullerene OSCs at present. It is noteworthy that the ternary OSCs also show great tolerance to film thickness and blend ratios. These unique properties are attributed to the hydrogen-bond-linked DIBC and PC 71 BM, which modulates molecule distribution and improves film morphology with an interpenetrating network structure. Furthermore, the DIBC containing device also exhibits good thermal and light radiation stability. These results illustrate that intermolecular hydrogen bond interaction has great potential for realizing high-performance OSCs.

Substituent-Controlled Tailoring of Chalcogen-Bonded Supramolecular Nanoribbons in the Solid State

“… 6 − 10 Among the several noncovalent interactions, hydrogen bonds embody the main interaction occurring in biological systems, 11 , 12 as well as being used for many applications in chemistry and materials science. 13 − 16 However, over the past decades, there has been a flourishing interest for a class of exotic noncovalent interactions, namely, Secondary Bonding Interactions (SBIs), 17 as attractive alternatives to the ubiquitous hydrogen bond in crystal engineering. SBIs’ nature relies on electrostatic (explained in terms of σ-holes) 18 and van der Waals contributions, as well as on orbital mixing described as n 2 (Y)→σ*(E-X) donation (X-E···Y), which involves nonbonding electrons of the electron-donating atom Y and the empty antibonding located on the E atom.…”

Fluorination Effect for Highly Conjugated Alternating Copolymers Involving Thienylenevinylene-Thiophene-Flanked Benzodithiophene and Benzothiadiazole Subunits in Photovoltaic Application

“…Supplementary Materials: The following are available online at www.mdpi.com/xxx/s1, Scheme S1: The synthetic route of fluorinated dibromide FBTBr2, Figure S1: 1 H NMR spectrum of BTBr2 in CDCl3, Figure S2: 13 C NMR spectrum of FBTBr2 in CDCl3, Figure S3: 1 H NMR spectrum of BDT-TVTSn in CDCl3, Figure S4: 13 C NMR spectrum of BDT-TVTSn in CDCl3, Table S1: Yields, GPC data and thermal properties for the studied copolymers, Table S2: The photovoltaic performance of the PSCs devices under varied fabrication processes, Table S3: Hole mobilities of the optimized devices measured by SCLC model, Table S4: Electron mobilities of the optimized device measured by SCLC model, Figure S5: UV-vis absorption spectra of copolymers PBDT-TVT-BT and PBDT-TVT-FBT dissolved in CB at various concentrations and calculation of molar absorption coefficient, Figure S6: J-V curves of PBDT-TVT-BT and PBDT-TVT-FBT with different weight ratio to PC71BM, and using 3%DIO additive and EQE spectra of corresponding PSCs, Figure S7: J-V curves of hole-only (a) and electrononly (b) devices for the PBDT-TVT-BT:PC71BM and PBDT-TVT-FBT:PC71BM.…”

“…Of all the third generation solar cell technologies (i.e., organic solar cells, perovskite solar cells, and dye-sensitized solar cells, and so on), bulk-heterojunction (BHJ) polymer solar cells (PSCs) have attracted broad academic and industrial interests, because of attractive features including flexibility, lightweight, large area, low-cost production, and environmental friendliness [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The photovoltaic performance of BHJ PSCs was highly dependent on the semiconductor materials used as the photoactive layer.…”

Introducing Trifluoromethyl to Strengthen Hydrogen Bond for High Efficiency Organic Solar Cells

“…Fourier Transform infrared spectroscopy (FT-IR) was used to determine whether hydrogen bonds formed (Du et al, 2019). In Figure 1B, the pure DTBO film has a sharp wave trough at 3,356 cm −1 which is the characteristic wave trough of N-H bond, when adding different molar ratios of IEICO-4F the wave trough gradually moved to 3,338 cm −1 .…”