Design of mechanically-robust naphthalenediimide-based polymer additives for high-performance, intrinsically-stretchable polymer solar cells

Abstract

High-molecular-weight electro-active polymer acceptor (PA) is effective in simultaneously increasing photovoltaic performance and mechanical integrity of polymer solar cells (PSCs) based on a polymer donor (PD) and a small molecule...

Investigating the Effects of Hydrogen Bonding on Mechanical and Electrical Properties of n-Type Semicrystalline Polymers

“…(Table 1). To precisely investigate (1) H-bonding and (2) terpolymer effects in the five different polymers by excluding M w effects, 55,56 we used a similar M w range of 133−180 kg mol −1 for all five polymers appending "-H" (high) at the end of their names to indicate the controlled parameter and for comparison to lower M w samples (vide infra). We also performed 1 H nuclear magnetic resonance (NMR) to confirm the presence of dimeric H-bonding interactions (Figures S7 and S8).…”

“…The M c is the point at which polymer chains begin to entangle, 58 resulting in a significant enhancement of the mechanical properties of the polymers. 55,56 For example, it is reported that N2200 polymer films with M w below M c exhibit brittle fracture behavior with a COS value lower than 3%, due to the absence of entanglement networks in the film. 25,56 However, the COS of the N2200 film significantly increases to above 30% once the M w exceeds the M c .…”

“…55,56 For example, it is reported that N2200 polymer films with M w below M c exhibit brittle fracture behavior with a COS value lower than 3%, due to the absence of entanglement networks in the film. 25,56 However, the COS of the N2200 film significantly increases to above 30% once the M w exceeds the M c . Thus, for comparative studies, a series of N2200 polymers were prepared with M w values of 51 (N2200-very low (VL)), 83 (N2200-low (L)), 112 (N2200-middle (M)), and 180 kg mol −1 (N2200-H).…”

“…58 In contrast, for N2200, the T m and ΔH m values linearly increased in the investigated M w ranges (Figure S11), suggesting that the M c of N2200 is above M w = 180 kg mol −1 . 55,56,60,61 To investigate the effects of (1) H-bonding and (2) terpolymer architecture on thermal properties, we conducted DSC analyses of N2200-H, Thy10-H, Dap10-H, Qx10-H, and Ester10-H. Despite all polymers showing similar M w , the four terpolymers exhibited lower T m values (255−310 °C) in second heating cycles, compared to 326 °C for N2200-H (Figure 2c).…”

“…This result indicates that polymer chains above the M c threshold tend to form a much higher degree of aggregation. 56 Additionally, the presence of H-bonding on the polymer chains contributes to stronger intermolecular interaction than polymers without H-bonding, as evidenced by significantly higher η sp values of Thy10-H and Dap10-H, compared to N2200-H (η sp = 0.8). 25 The aggregation behaviors of polymers were compared using UV−vis spectroscopy in both solution and film states (Figures S12−S14).…”