A Novel Donor-Acceptor-Acceptor-Acceptor Polymer Containing Benzodithiophene and Benzimidazole-Benzothiadiazole-Benzimidazole for PSCs

Abstract

New electron deficient acceptor-acceptor-acceptor type of monomer unit composed of weak electron accepting benzimidazole and relatively strong electron accepting benzothiadiazole derivatives namely 4,7-bis(6-bromo- The opto-electrical studies revealed that the absorption band of PBDTBBB appeared in the range of 300 nm-525 nm and its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were positioned at −5.18 eV and −2.84 eV, respectively. The power conversion efficiency (PCE) of the polymer solar cell (PSC) prepared from PBDTBBB:PC 71 BM (1:2 wt %) blend was 1.90%.

Property modulation of benzodithiophene-based polymers via the incorporation of a covalently bonded novel 2,1,3-benzothiadiazole-1,2,4-oxadiazole derivative in their main chain for polymer solar cells

“…Earlier reports conrmed that the incorporation of sterically hindered electron donor groups, such as 3octylthiophene or alkoxy benzene, or an electron accepting benzimidazole derivative on both sides of the BT restrict the ICT from the donor to the acceptor units when they are polymerized with electron-rich units. 15,17,23,34 These results suggest that the incorporation of Oxa units on both sides of the BT unit also diminish the ICT between the D-A units. The absorption onset wavelengths of P(BDT-BBOB) and P(BDT-BOB) were calculated to be 534 nm and 622 nm, respectively, from which the optical band gaps (E g,opt ) were determined to be 2.32 eV and 1.99 eV, respectively.…”

“…8 Consequently, many studies have shown that the photovoltaic properties of the polymers incorporating BT-based acceptor units can be tuned via the incorporation/insertion of electron donating or accepting units on the BT moiety. [15][16][17][18][19][20][21][22][23][24][25][26][27][28] In most of the studies, electron donating units, [15][16][17][18][19][20][21] such as benzene, thiophene, thienothiophene, and furan derivatives, are covalently attached on both sides of the BT unit or electron-rich alkoxy, 20,21 or electron-attracting uorides 8,28 are inserted on the back bone of the BT unit with the aim being to improve the absorption and carrier mobility and to tune the energy levels of the BT-based polymers. In addition, electron accepting units, such as thiazole 22 and benzimidazole, 23 are also attached on both sides of the BT units or quinoxaline, 24,25 and thiadiazole 26 and N-alkylpyrrolidine-2,5-dione rings 27 are fused on the BT back bone with the aim being to increase the electron attracting ability of the BT unit.…”

Electrochromic two-dimensional covalent organic framework with a reversible dark-to-transparent switch

“…The building units of TPBD and BTDD were synthesised according to the reported methods with slight modifications (see in Supporting Information) 39,40 . The 2D COF was prepared as follows: after dissolving TPBD and BTDD in a mixed solvent of 1,2-dichlorobenzene:n-butanol (v:v = 1:1) and ultrasonicating 20 min to generate a dark purple solution, acetic acid (6 M) was added, followed by rapid freezing to 77 K, degassed through three cycles of freeze-pump-thaw, and sealed under vacuum.…”

“…5). The non-local density function theory [31][32][33][34][35][36][37][38][39][40][41][42] was employed to estimate a pore size distribution of~1.8 nm (Supplementary Fig. 5).…”

“…Here, we show a D-A two-dimensional (2D) COF with N,N,N′,N′ -tetrakis(p-aminophenyl)-p-benzenediamine (TPBD) 39 as donor, and 2,1,3-benzothiadiazole-4,7-dicarboxaldehyde (BTDD) as acceptor 40 , was prepared ( Fig. 1 and Supplementary Fig.…”