A solar module and a method for fabricating a solar module comprising a plurality of rear contact solar cells are described. Rear contact solar cells (1) are provided with a large size of e.g. 156156 mm.sup.2, Soldering pad arrangements (13, 15) applied on emitter contacts (5) and base contacts (7) are provided with one or more soldering pads (9, 11) arranged linearly. The soldering pad arrangements (13, 15) are arranged asymmetrically with respect to a longitudinal axis (17). Each solar cell (1) is then separated into first and second cell portions (19, 21) along a line (23) perpendicular to the longitudinal axis (17). Due to such cell separation and the asymmetrical design of the soldering pad arrangements (13, 15), the first and second cell portions (19, 21) may then be arranged alternately along a line with each second cell portion (21) arranged in a 180-orientation with respect to the first cell portions (19) and such that emitter soldering pad arrangements (13) of a first cell portion (19) are aligned with base soldering pad arrangements (15) of neighboring second cell portions (21), and vice versa. Simple linear ribbon-type connector strips (25) may be used for interconnecting the cell portions (19, 21) by soldering onto the underlying aligned emitter and base soldering pad arrangements (13, 15). The interconnection approach enables using standard ribbon-type connector strips (25) while reducing any bow as well as reducing series resistance losses.

A solar cell including a semiconductor substrate having a first conductivity type an emitter region, having a second conductivity type opposite to the first conductivity type, on a first main surface of the semiconductor substrate an emitter electrode which is in contact with the emitter region a base region having the first conductivity type a base electrode which is in contact with the base region and an insulator film for preventing an electrical short-circuit between the emitter region and the base region, wherein the insulator film is made of a polyimide, and the insulator film has a C.sub.6H.sub.11O.sub.2 detection count number of 100 or less when the insulator film is irradiated with Bi.sub.5.sup.++ ions with an acceleration voltage of 30 kV and an ion current of 0.2 pA by a TOF-SIMS method. There can be provided a solar cell having excellent weather resistance and high photoelectric conversion characteristics.

Improved high work function back contacts for solar cells are provided. In one aspect, a method of forming a solar cell includes: forming a completed solar cell having a substrate coated with an electrically conductive material, an absorber disposed on the electrically conductive material, a buffer layer disposed on the absorber, a transparent front contact disposed on the buffer layer, and a metal grid disposed on the transparent front contact; removing the substrate and the electrically conductive material using exfoliation, exposing a backside surface of the solar cell; depositing a high work function material onto the back side surface of the solar cell; and depositing a back contact onto the high work function material. A solar cell formed by the present techniques is also provided. Yield of the exfoliated device can be improved by removing bubbles from adhesive used for exfoliation and/or forming contact pads to access the metal grid.

A photovoltaic conversion device (10) includes a semiconductor substrate (1), a passivation film (3), n-type amorphous semiconductor strips, p-type amorphous semiconductor strips (5p), and electrodes (7). The passivation film (3) is formed on one of the surfaces of the semiconductor substrate (1). The n- and p-type amorphous semiconductor strips are arranged alternately as viewed along an in-plane direction of the semiconductor substrate (1) (Y-axis direction). The p-type amorphous semiconductor strips (5p) have reduced-thickness regions (51) at some intervals as viewed along the length direction of the p-type amorphous semiconductor strips (5p) (X-axis direction). The n-type amorphous semiconductor strips have a similar structure. The electrodes (7) are provided on the p-type amorphous semiconductor strips (5p), but not in areas where the reduced-thickness regions (51) have a positive curvature r with respect to the length direction of the reduced-thickness regions (51). Electrodes on the n-type amorphous semiconductor strips have a similar arrangement.

A solar panel is provided with a stack including at least one back contacted solar cell and a back-sheet layer. The back-sheet layer has a patterned conductive layer of a first material. The conductive layer is arranged with contacting areas each located at a location corresponding to a location of an electrical contact on the solar cell. The solar cell is arranged on top of the conductive layer with the rear surface of the solar cell facing the patterned conductive surface. Each electrical contact of the solar cell is in contact with a corresponding contacting area on the conductor circuit by a body of conductive connecting material. The conductive layer includes at the location of the contacting area a patch of a second material. Each patch is arranged in between the body of conductive connecting material on one electrical contact and the layer of the first material.

A stacked multi-junction solar cell with a front side contacted through the rear side and having a solar cell stack having a Ge substrate layer, a Ge subcell, and at least two III-V subcells, with a through contact opening, a front terminal contact, a rear terminal contact, an antireflection layer formed on a part of the front side of the multi-junction solar cell, a dielectric insulating layer, and a contact layer. The dielectric insulating layer covers the antireflection layer, an edge region of a top of the front terminal contact, a lateral surface of the through contact opening, and a region of the rear side of the solar cell stack adjacent to the through contact opening. The contact layer from a region of the top of the front terminal contact that is not covered by the dielectric insulating layer through the through contact opening to the rear side.

A method for structuring an insulating layer on a semiconductor wafer includes providing a semiconductor wafer with a top, a bottom and includes multiple solar cell stacks, wherein each solar cell stack is a Ge substrate, which forms the bottom of the semiconductor wafer, a Ge subcell and at least two III-V subcells, in the above order, and at least one passage opening, which extends from the top to the bottom of the semiconductor wafer and has a connected side wall, an insulating layer two-dimensionally deposited on the top of the semiconductor wafer, on the side wall of the passage opening and/or on the bottom of the semiconductor wafer, and the deposition of an etch-resistant filling material by means of a printing process on an area of the top which include the passage opening, and into the passage opening.

An example of an apparatus to convert light energy to electrical energy is provided. The apparatus includes a semiconductor material to absorb energy from a photon. The energy is to be converted to a current. Furthermore, the apparatus includes a positive electrode disposed on a backside of the semiconductor material to collect the current from the backside. In addition, the apparatus includes a via to connect the backside of the semiconductor material electrically to a frontside of the semiconductor material. The apparatus also includes a plurality of fingers disposed on the frontside of the semiconductor material to collect the current from the frontside. The apparatus further includes a trunkline connected to the plurality of fingers to deliver the current to the via. The trunkline is to increase a cross-sectional area toward the via to reduce parasitic resistance.

Approaches for the foil-based metallization of solar cells and the resulting solar cells are described. In an example, a solar cell includes a substrate. A plurality of alternating N-type and P-type semiconductor regions is disposed in or above the substrate. A conductive contact structure is disposed above the plurality of alternating N-type and P-type semiconductor regions. The conductive contact structure includes a plurality of metal seed material regions providing a metal seed material region disposed on each of the alternating N-type and P-type semiconductor regions. A metal foil is disposed on the plurality of metal seed material regions, the metal foil having anodized portions isolating metal regions of the metal foil corresponding to the alternating N-type and P-type semiconductor regions.

The present invention relates to a method for metallizing a front electrode of an N-type solar cell, including: treating an N-type crystalline silicon substrate to form a p.sup.+ doped region and a front surface passivation anti-reflection coating on a front surface of the N-type crystalline silicon substrate in an inside-out sequence, printing an aluminum paste on the front surface passivation anti-reflection coating to form a first finger, overprinting a silver paste on the first finger to form a second finger, and printing a front silver paste on the first finger to form a busbar. In the present invention, the superposition of the second finger on the first finger can reduce line resistance while ensuring a good ohmic contact, which further improves the photoelectric conversion efficiency of solar cells. Moreover, since no grooving procedure is required, the process is simplified and cost-efficient.