Organic Solar Modules: Fully Doctor Bladed on Glass in Air

Abstract

For future integration into building facades or overhead glazing, the direct deposition of organic solar modules on glass substrates in sheet‐to‐sheet processes may be more cost efficient than postproduction lamination. Complying with the special requirements for the deposition of the layer stack on glass substrates, we report on all‐doctor‐bladed organic solar modules yielding power conversion efficiencies of 4.5 and 3.6 % on photoactive areas of 1 and 20 cm2, respectively. The bottom electrode is doctor bladed from a silver ink atop an adhesion enhancing primer. The top electrode is applied from silver nanowires, dispersed in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), which thereby avoids any visible bus bars and reduces shading of the active layer. Importantly, all layers are deposited under ambient conditions by using only non‐chlorinated, eco‐compatible solvents.

Solar Glasses: A Case Study on Semitransparent Organic Solar Cells for Self‐Powered, Smart, Wearable Devices

“…[11] It is also suitable for depositing absorber layers with thicknesses beyond 250 nm on al arge scale and can be processed in air without detrimental effects on the device performance or stability. [11,14] Thea bsorber blend was dissolved and processedf rom am ixture of the solvent o-xylene and the co-solvent p-anisal-dehyde,w hich forms av ery suitable and fastd rying alternative to the often-used toxic halogenated solvents. [12,14,15] Forr eference,w ef irst investigatedo paque reference solar cells with an inverted glass/indium tin oxide (ITO)/zinc oxide (ZnO)/PBTZT-stat-BDTT-8:PC 61 BM:PC 71 BM/molybdenum oxide (MoO x )/silver( Ag)d evice architecture and ar ather small photoactive area of 0.105 cm 2 ,y ielding as hort-circuit current density of J sc = 14.2 mA cm À2 ,a no pen-circuit voltage of V OC = 757 mV,afill factor of FF = 70 %, and resultingi n PCE = 7.4 %.…”

“…[11,14] Thea bsorber blend was dissolved and processedf rom am ixture of the solvent o-xylene and the co-solvent p-anisal-dehyde,w hich forms av ery suitable and fastd rying alternative to the often-used toxic halogenated solvents. [12,14,15] Forr eference,w ef irst investigatedo paque reference solar cells with an inverted glass/indium tin oxide (ITO)/zinc oxide (ZnO)/PBTZT-stat-BDTT-8:PC 61 BM:PC 71 BM/molybdenum oxide (MoO x )/silver( Ag)d evice architecture and ar ather small photoactive area of 0.105 cm 2 ,y ielding as hort-circuit current density of J sc = 14.2 mA cm À2 ,a no pen-circuit voltage of V OC = 757 mV,afill factor of FF = 70 %, and resultingi n PCE = 7.4 %. Then we replaced the opaque MoO x /Ag electrode with as olution-processed transparent conductive poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer and, for technical reasons, increased the photoactive area of the solar cell to 0.24 cm 2 .D espite the missing reflective counter electrodea nd the increased series resistance of the polymer electrode,t he semitransparent device exhibited a PCE = 4.8 %( J sc = 12.2 mA cm À2 , V OC = 756 V, FF = 52 %).…”

“…We notet hat the resistive losses in the PEDOT:PSS electrode can be reducedb yu sing aP EDOT:PSSf ormulation with lower specific resistance [12,14] or by dividing the device into monolithically connected subcells (e.g.,u sing am odule layout). However, even with employing laser structuring to separate the cells by fine lines and despite being slightly out of the eyesf ocus,s uch interconnects may be perceivable by the user of the solar glassest hrough local changes in transparency or scattering effects.T herefore,w ed eliberately decided to fit each lens with only one large solar cell.…”

Hot‐Pressed Hybrid Electrodes Comprising Silver Nanowires and Conductive Polymers for Mechanically Robust, All‐Doctor‐Bladed Semitransparent Organic Solar Cells

“…They served as bottom electrodes for organic light emitting devices that were built by vacuum depositing all further layers. In earlier works, we reported on silver nanowire top electrodes embedded in PEDOT:PSS matrices, which were implemented as one‐layer transparent top electrodes for both opaque and semitransparent devices …”

“…Mechanicalr obustness is even more important for future industrial device fabrication where plastic foils may wind and unwind at high speed in roll-to-roll production plants.H ere, the electrodes of the solar cells play ap ivotal role.T ransparent sputter-deposited indium tin oxide (ITO) electrodes and vacuum-deposited metal counter electrodes are often used in principal lab experiments,but their use in large-scale production by printing is severely limited. Various concepts for printable electrodes have been reported in the literature, among them metal inks, [12][13][14][15][16] metal grids, [17][18][19] highly conductive polymers, [17,[20][21][22][23] silver nanowires [20,[24][25][26][27][28] (AgNWs),a nd combinations thereof. [16,[29][30][31][32][33][34][35] Employing ac ombination of conductive polymers and nanowires always brings the risk of devices hunting from individual nanowires that stick out of the electrodes,w hich particularly limits their use in bottom electrodes.T he first attempts to flattens uch electrodes were performed on as mall scale using rigid glass substrates cov-Future low-cost, high-throughput production of organic solar cells in roll-to-roll printing processes calls for all-solutionprocessable device architectures.M echanicalf lexibility and robustness are mandatory to roll the solar foils duringp rinting and to eventually complyw ith certain end-user requirements.H ere,w er eport on semitransparent organic solar cells,c omprising top and bottom silver nanowire (AgNW) electrodes that were embedded into conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).…”