Grid-line-free and undoped-contact based monocrystalline silicon heterojunction solar cell

Abstract

The invention discloses a grid-line-free and undoped-contact based monocrystalline silicon heterojunction solar cell. The solar cell successively comprises an antireflection film, an ultrathin metal film, hole selective contact, monocrystalline silicon, electron selective contact and a back electrode from top to bottom. The ultrathin metal film is a continuous film, and a thickness is less than 10nm. The hole selective contact and the electron selective contact can be two layers or one layer respectively. In the invention, the ultrathin metal film is introduced so that a shielding effect of agrid line electrode in a traditional cell on sunlight is avoided, collection efficiency of a photon-generated carrier is improved, a limiting effect on long-waveband sunlight is enhanced, and a short-circuit current of the cell can be greatly improved; the metal film can also improve stability of the cell and increase flexibility of the cell; and the whole cell is simple in structure, flexible indesign, and simple in process, an extra doping process is not needed, an electrode pattern structure does not need to be defined, a process temperature can be controlled within 100 DEG C, and cost islow.

Description

technical field [0001] The invention relates to the field of solar photovoltaic technology, in particular to a single-crystal silicon heterojunction solar cell based on no grid lines and no doped contacts. Background technique [0002] Monocrystalline silicon solar cells occupy the most important photovoltaic market in the world and are an important photovoltaic technology solution. The traditional monocrystalline silicon photovoltaic technology is represented by two kinds of solar cells, homojunction and heterojunction. The former adopts p+ type hole selective contact and n+ type electron selective contact formed by diffusion doping; Crystalline silicon is used as a passivation layer, and p+ type and n+ type heavily doped amorphous silicon are used as hole and electron selective contacts. These doped contact technologies have many disadvantages: From a physical perspective, heavy doping will inevitably lead to unfavorable factors such as Auger recombination, narrowing of t...

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Problems solved by technology

These doped contact technologies have many disadvantages: From a physical perspective, heavy doping will inevitably lead to unfavorable factors such as Auger recombination, narrowing of the forbidden band, body / surface recombination, and free carrier absorption, which greatly limit the open circuit voltage of the battery. and short-circuit current; from a technical point of view, doping often requires high-temperature diffusion and annealing processes, and also requires highly toxic gases (borane and phosphine) to grow p+ type and n+ type amorphous silicon, the process is complex and the cost is high

There are few reports on single crystal silicon heterojunction solar cells with both electron and hole selective contacts without doping

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