Carrier Formation Dynamics in Prototypical Organic Solar Cells as Investigated by Transient Absorption Spectroscopy

<div>Absolute number of carriers (<svg height="9.14241pt" id="M121" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 18.5329 9.14241" width="18.5329pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M495 86L479 114C446 82 419 66 409 66C401 66 401 72 406 97C420 166 436 231 453 297C489 435 454 448 428 448C406 448 384 439 354 422C305 394 222 327 161 247H159L183 345C200 415 194 448 173 448C143 448 82 410 23 351L38 325C64 349 95 371 105 371C111 371 116 365 109 336L25 -4L31 -12C50 -4 77 3 107 9C119 69 132 122 145 168C197 254 321 381 370 381C387 381 393 374 378 305L329 95C309 17 320 -12 345 -12C372 -12 430 19 495 86Z" id="g113-111"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="502" vert-adv-y="502"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,6.461,3.132)"><path d="M43 650V617C122 612 130 606 130 522V128C130 44 122 37 34 32V0H275C400 0 497 25 573 82C652 142 698 229 698 350C698 445 662 518 613 565C549 625 456 650 327 650H43ZM217 544C217 580 220 591 229 599C240 607 264 613 311 613C380 613 437 599 482 570C561 523 598 436 598 336C598 177 511 40 324 40C248 40 217 61 217 135V544Z" id="g58-66"></path><glyph.data ascent="1007" descent="-369" horiz-adv-x="744" vert-adv-y="744"></glyph.data></g><g transform="matrix(.0065,0,0,-0.0065,13.231,-.065)"><path d="M578 242V297H351V519H286V297H59V242H286V-6H351V242H578Z" id="g180-36"></path><glyph.data ascent="3439" descent="-2858" horiz-adv-x="637" vert-adv-y="637"></glyph.data></g></svg>), donor excitons (<svg height="9.14241pt" id="M122" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 18.5329 9.14241" width="18.5329pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M495 86L479 114C446 82 419 66 409 66C401 66 401 72 406 97C420 166 436 231 453 297C489 435 454 448 428 448C406 448 384 439 354 422C305 394 222 327 161 247H159L183 345C200 415 194 448 173 448C143 448 82 410 23 351L38 325C64 349 95 371 105 371C111 371 116 365 109 336L25 -4L31 -12C50 -4 77 3 107 9C119 69 132 122 145 168C197 254 321 381 370 381C387 381 393 374 378 305L329 95C309 17 320 -12 345 -12C372 -12 430 19 495 86Z" id="g113-111"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="502" vert-adv-y="502"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,6.461,3.132)"><path d="M43 650V617C122 612 130 606 130 522V128C130 44 122 37 34 32V0H275C400 0 497 25 573 82C652 142 698 229 698 350C698 445 662 518 613 565C549 625 456 650 327 650H43ZM217 544C217 580 220 591 229 599C240 607 264 613 311 613C380 613 437 599 482 570C561 523 598 436 598 336C598 177 511 40 324 40C248 40 217 61 217 135V544Z" id="g58-66"></path><glyph.data ascent="1007" descent="-369" horiz-adv-x="744" vert-adv-y="744"></glyph.data></g><g transform="matrix(.0065,0,0,-0.0065,13.231,-.065)"><path d="M503 164C503 183 495 209 482 228C429 236 402 243 352 269C402 295 428 304 482 311C494 330 503 355 502 376C485 385 459 391 436 390C403 347 383 328 336 298C338 354 343 381 365 431C353 451 337 471 318 481C302 471 283 451 273 431C293 381 300 354 303 298C255 328 235 346 202 389C179 390 153 385 135 374C135 355 143 329 156 310C210 302 236 295 286 269C236 243 210 234 156 227C144 208 135 183 136 162C153 153 180 147 202 148C235 191 255 210 303 240C300 184 295 157 274 107C285 87 301 67 320 57C337 67 355 87 365 107C345 157 339 184 336 240C383 210 404 192 436 149C460 148 485 153 503 164Z" id="g176-43"></path><glyph.data ascent="3439" descent="-2858" horiz-adv-x="637" vert-adv-y="637"></glyph.data></g></svg>), and acceptor excitons (<svg height="9.14241pt" id="M123" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 18.1584 9.14241" width="18.1584pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M495 86L479 114C446 82 419 66 409 66C401 66 401 72 406 97C420 166 436 231 453 297C489 435 454 448 428 448C406 448 384 439 354 422C305 394 222 327 161 247H159L183 345C200 415 194 448 173 448C143 448 82 410 23 351L38 325C64 349 95 371 105 371C111 371 116 365 109 336L25 -4L31 -12C50 -4 77 3 107 9C119 69 132 122 145 168C197 254 321 381 370 381C387 381 393 374 378 305L329 95C309 17 320 -12 345 -12C372 -12 430 19 495 86Z" id="g113-111"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="502" vert-adv-y="502"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,6.461,3.132)"><path d="M682 0V33C615 38 603 49 571 134C507 305 441 494 378 665L343 655L136 136C101 48 86 41 22 33V0H246V33C170 41 161 50 183 112C196 152 209 192 224 232H441C461 176 478 126 493 87C504 49 499 41 433 33V0H682ZM425 279H242C273 363 303 448 335 533H337L425 279Z" id="g58-63"></path><glyph.data ascent="1007" descent="-369" horiz-adv-x="703" vert-adv-y="703"></glyph.data></g><g transform="matrix(.0065,0,0,-0.0065,12.858,-.065)"><path d="M503 164C503 183 495 209 482 228C429 236 402 243 352 269C402 295 428 304 482 311C494 330 503 355 502 376C485 385 459 391 436 390C403 347 383 328 336 298C338 354 343 381 365 431C353 451 337 471 318 481C302 471 283 451 273 431C293 381 300 354 303 298C255 328 235 346 202 389C179 390 153 385 135 374C135 355 143 329 156 310C210 302 236 295 286 269C236 243 210 234 156 227C144 208 135 183 136 162C153 153 180 147 202 148C235 191 255 210 303 240C300 184 295 157 274 107C285 87 301 67 320 57C337 67 355 87 365 107C345 157 339 184 336 240C383 210 404 192 436 149C460 148 485 153 503 164Z" id="g176-43"></path><glyph.data ascent="3439" descent="-2858" horiz-adv-x="637" vert-adv-y="637"></glyph.data></g></svg>) per an absorbed photon against the delay time in PTB7/PC<sub>71</sub>BM blend film. Adjacent averages were plotted in <svg height="9.14241pt" id="M124" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 18.1584 9.14241" width="18.1584pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M495 86L479 114C446 82 419 66 409 66C401 66 401 72 406 97C420 166 436 231 453 297C489 435 454 448 428 448C406 448 384 439 354 422C305 394 222 327 161 247H159L183 345C200 415 194 448 173 448C143 448 82 410 23 351L38 325C64 349 95 371 105 371C111 371 116 365 109 336L25 -4L31 -12C50 -4 77 3 107 9C119 69 132 122 145 168C197 254 321 381 370 381C387 381 393 374 378 305L329 95C309 17 320 -12 345 -12C372 -12 430 19 495 86Z" id="g113-111"></path><glyph.data ascent="3473" descent="-2876" horiz-adv-x="502" vert-adv-y="502"></glyph.data></g><g transform="matrix(.0091,0,0,-0.0091,6.461,3.132)"><path d="M682 0V33C615 38 603 49 571 134C507 305 441 494 378 665L343 655L136 136C101 48 86 41 22 33V0H246V33C170 41 161 50 183 112C196 152 209 192 224 232H441C461 176 478 126 493 87C504 49 499 41 433 33V0H682ZM425 279H242C273 363 303 448 335 533H337L425 279Z" id="g58-63"></path><glyph.data ascent="1007" descent="-369" horiz-adv-x="703" vert-adv-y="703"></glyph.data></g><g transform="matrix(.0065,0,0,-0.0065,12.858,-.065)"><path d="M503 164C503 183 495 209 482 228C429 236 402 243 352 269C402 295 428 304 482 311C494 330 503 355 502 376C485 385 459 391 436 390C403 347 383 328 336 298C338 354 343 381 365 431C353 451 337 471 318 481C302 471 283 451 273 431C293 381 300 354 303 298C255 328 235 346 202 389C179 390 153 385 135 374C135 355 143 329 156 310C210 302 236 295 286 269C236 243 210 234 156 227C144 208 135 183 136 162C153 153 180 147 202 148C235 191 255 210 303 240C300 184 295 157 274 107C285 87 301 67 320 57C337 67 355 87 365 107C345 157 339 184 336 240C383 210 404 192 436 149C460 148 485 153 503 164Z" id="g176-43"></path><glyph.data ascent="3439" descent="-2858" horiz-adv-x="637" vert-adv-y="637"></glyph.data></g></svg>. The solid curves are results of the least-squares fittings with exponential functions.</div>

International Journal of Photoenergy

fig8

Figure 8

Figure 8: Carrier Formation Dynamics in Prototypical Organic Solar Cells as Investigated by Transient Absorption Spectroscopy 